Systems and processes for conversion of ethylene feedstocks to hydrocarbon fuels

ABSTRACT

Systems, processes, and catalysts are disclosed for obtaining fuels and fuel blends containing selected ratios of open-chain and closed-chain fuel-range hydrocarbons suitable for production of alternate fuels including gasolines, jet fuels, and diesel fuels. Fuel-range hydrocarbons may be derived from ethylene-containing feedstocks and ethanol-containing feedstocks.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/528,185, filed on Oct. 30, 2014, which is incorporated herein byreference in its entirety.

STATEMENT REGARDING RIGHTS TO INVENTION MADE UNDER FEDERALLY-SPONSOREDRESEARCH AND DEVELOPMENT

This invention was made with Government support under ContractDE-AC05-76RL01830 awarded by the U.S. Department of Energy. TheGovernment has certain rights in the invention.

FIELD OF THE INVENTION

The present invention relates generally to processes and catalysts forconversion of hydrocarbon feedstocks. More particularly, the inventionrelates to a system, processes, and catalysts for conversion ofethylene-containing feedstocks to fuel-range hydrocarbon distillatessuitable for production of fuels.

BACKGROUND OF THE INVENTION

Currently a need exists for alternative hydrocarbon fuels, especiallyaviation and diesel fuels, from domestic sources to enhance energysecurity and to decrease reliance on foreign petroleum. Current routesto alternative fuels are limited by strict fuel standards and limitedfuel feed stocks. And, many fuel and fuel blend stocks requireopen-chain hydrocarbons including, e.g., normal paraffins and branchedparaffins. For example, according to ASTM D7566-11a standards,hydrogenated HEFA/SPK (Hydroprocessed Esters and Fatty Acids/SyntheticParaffinic Kerosene) from bio-derived fats and oils and fromFischer-Tropsch reactions of syngas can only contain a maximum of 0.5%aromatics and 15% cycloparaffins. In addition, an average JP-8 jet fuelcontains 59% normal and iso-paraffins, the remainder being aromatics andcycloparaffins. However, many conventional methods for producingalternate fuels such as from biomass feedstocks cannot meet theserequirements. For example, pyrolysis and hydrothermal liquefaction ofterrestrial biomass feedstocks form aromatics predominately and, whenhydrotreated, yield cyclic hydrocarbons. Ethanol and other oxygenatedhydrocarbons are suitable for direct blending with gasoline, butoxygenated hydrocarbons are precluded for use in jet fuels. Ethanol canbe converted to liquid hydrocarbons over solid acid catalysts only attemperatures above about 300° C., but the products are largely aromatics(75%-90%). Thus, aviation and military organizations can expectdifficulties meeting renewable fuel standards for jet fuels and dieselfuels using conventional technologies. Yet, ethanol is available in themarket place. Thus, converting ethanol to oxygen-free open-chainhydrocarbons could permit their use in diesel and jet fuels. Morespecifically, catalytic conversion of renewable ethanol to oxygen-freeopen-chain hydrocarbons could allow for production of renewable fuelsfrom oxygenated renewable feedstocks, such as carbohydrates andlignocellulosic biomass.

Ethylene is a feedstock available from numerous sources that could beconverted to alternate open-chain hydrocarbon fuels. Ethylene can beobtained from sources such as natural gas, coal, and petroleum. Ethyleneis also obtainable by known technologies from ethanol, which in turn canbe made from biomass-derived sugars and starch and from syngas. Ethanoltherefore can be considered an ethylene precursor. However, conversionof ethylene via conventional direct, single step conversion processescatalyzed by solid acid catalysts, such as silicoaluminates, istypically characterized by high process temperatures (>280° C.) thatform large quantities of coke, and extensive formation of aromaticcompounds up to 70 wt %. Single-step processes such as that reported byHeveling et al. over Ni/Si—Al and other catalysts are reported toproduce open-chain hydrocarbons at high ethylene conversions, but withselectivities to ≥C10 of only ca 40% and to ≥C8 of only about 63%.Further, multi-step conversion processes reported in the literature havepotentially better selectivities to open-chain compounds, butconversions to date are low and significant quantities of aromaticcompounds are produced. For example, Synfuels International reports amulti-step process using Ni catalysts at process temperatures from 220°C. to 240° C. that produces a product composition containing between 4%to 90% aromatics. At the reported maximum selectivity of 70% middledistillate products and an ethylene conversion of only 26%, the maximumpossible product yield in the middle distillate range is only about 18%.The 2-step Synfuels International process does not improve upon and, infact, gives a lower distillate yield (18%) than the 1-step processreported by Heveling (40%). Thus, the 2-step approach by SynfuelsInternational does not represent an economically feasible approach forobtaining high yields of distillate fuels. Accordingly, new processesand catalysts are needed that convert ethylene obtained, e.g., fromvarious ethanol feedstocks into suitable oxygen-free hydrocarbon fuelblend stocks that minimize the production of aromatic hydrocarbons andthe quantity of hydrogen needed to produce fuels, and that produce fuelprecursors and/or fuel blend stocks that maximize flexibility inblending ratios suitable for production of jet fuel, other aviationfuels, diesel, and heating fuels. The present invention addresses theseneeds using, surprisingly, a 2-step method that provides distillateyields greater than the 18% of the prior art.

Definitions

The following terms are defined herein for purposes of this application.

Fuel-Range Hydrocarbons: are defined as any oxygen-free hydrocarbon orhydrocarbon mixture with a carbon number ranging between about C8 andabout C23 that distills in a temperature range from about 120° C. toabout 390° C. Actual range limits for commercial use depend on numerousother required fuel properties. Thus, no limitations are intended.Fuel-range hydrocarbons can be fractionated to produce jet, diesel,other aviation fuels and fuel blend stocks suitable for commercial andmilitary applications, and heating fuels.

Jet Fuel and Jet-Range Hydrocarbons: are defined as any hydrocarbon orhydrocarbon mixture that distills in the range from about 120° C. toabout 300° C., and typically includes hydrocarbons with a carbon numberbetween about C8 and about C16. Actual range limits for commercial usedepend on numerous other required fuel properties. Thus, no limitationsare intended.

Diesel Fuel and Diesel-Range Hydrocarbons: are defined as anyhydrocarbon or hydrocarbon mixture that distills in the range of about160° C. to about 390° C., typically with a carbon number between aboutC11 and about C23. Actual range limits for commercial use depend onnumerous other required fuel properties. Thus, no limitations areintended.

Alternative Fuel—The term “alternative” refers to hydrocarbons derivedfrom non-petroleum sources, including renewable sources such as, e.g.,biomass, sugars, starches, lignocellulose, and other renewable sources,and other sources such as natural gas and coal.

Boiling Point Cut-Off: is a temperature defining the high or lowtemperature of a boiling point range. The degree to which materials arepresent that actually boil outside the defined range depends on theefficiency of the distillation apparatus and operating conditions sothat the cut-off points are to be considered approximate and are notabsolute. Boiling point cut-offs are determined herein by research andprocess chemistry needs and not necessarily by current industrystandards. Boiling point cut-offs that produce fuel fractions that meetindustrial standards from disclosed products are easily determined bythose of ordinary skill in the art using established testing andresearch methods and may differ from those defined here. Alternate termsare distillation cut-off point and fractionation temperature.

Light Products: are defined as any hydrocarbon or hydrocarbon mixturethat boils below a distillation cut-off point. An alternate term islight fraction.

Heavy Products: are defined as any hydrocarbon or hydrocarbon mixturethat boils above a distillation cut-off point. An alternate term isheavy fraction

Two-Step or Two-Stage—A two-step process or two-stage system describedherein employs two sequential olefin oligomerization process steps orsystem stages to produce fuel-range hydrocarbons. Other required andoptional process steps or system stages may be used to obtain desiredhydrocarbon fuels or fuel blend stocks with desired properties.

One-Step or One-Stage—A one-step process or one-stage system employs asingle ethanol oligomerization step or stage to produce fuel-rangehydrocarbons. Other required and optional process steps or system stagesmay be used to obtain desired hydrocarbon fuels or fuel blend stockswith desired properties.

Olefin—The term “olefin” or alternately, alkene, refers to anyunsaturated hydrocarbon containing at least one double bond positionedalong the length of the hydrocarbon chain. The hydrocarbon chain may bestraight (i.e., acyclic, linear, or normal), cyclic, or branched (e.g.,containing one or more hydrocarbon side-chains).

Weight Hourly Space Velocity (WHSV)—feedstock flow rate in grams/hourdivided by the catalyst weight in grams.

SUMMARY OF THE INVENTION

The present invention includes a two-step oligomerization process andtwo-stage oligomerization system for controlled catalytic conversion ofethylene-containing feedstocks that produce fuel-range hydrocarbondistillates containing primarily open-chain oligomers including, e.g.,normal paraffins and isoparaffins. The present invention achievesresults that conventional conversion processes cannot. For example, thepresent invention converts ethylene (or ethanol as a precursor toethylene) to distillate normal and isoparaffins with high ethyleneconversion (e.g., 50% to 100%), high product selectivities in thedistillate range (e.g., 75 wt %≥C8 and 55 wt %≥C10) in a single-passoperation (higher with recycle), and <4 wt % aromatic compounds prior tohydrotreating. Unreacted materials are easily recycled to increase fuelyields. As such, the present invention addresses the need for lowaromatic alternate fuels and fuel blend stocks.

The invention also includes a two-step process combined with a one-stepprocess and system for controlled catalytic conversion ofethylene-containing feedstocks (or ethanol as a precursor to ethylene)and ethanol-containing feedstocks to produce fuel-range hydrocarbondistillates containing open-chain oligomers including, e.g., normalparaffins and isoparaffins, and closed-chain oligomers including, e.g.,cyclic paraffins and aromatic hydrocarbons in any desired concentration.The combined process and system make a low aromatic fuel blend stock asdescribed above. The combined process employs a parallel one-stepprocess or one-stage system to produce an aromatic fuel blend stock. Forexample, ethanol can be converted in a one-step method over zeolytecatalysts to mostly aromatic hydrocarbons. In one application, thearomatics may be alkylated with olefin products obtained from a firstoligomerization reactor of a two-step process or two-stage system; withlight olefin products fractionated from the second oligomerizationreactor of the two-step process or two-stage system; or with ethylene toform higher molecular weight aromatic products in the distillate range.

In another application, the aromatic hydrocarbons can be reduced with acatalyst and hydrogen to prepare cyclic hydrocarbons. Thus, in thecombined process or combined system, one-step or one-stage productscomprising a fuel blend stock containing cyclic paraffins and aromaticscan be blended or mixed in any desired ratio with two-step or two-stageproducts comprising a fuel blend stock containing normal andisoparaffins to produce a fuel mixture containing all fuel components ofany desired composition

The two-step oligomerization process may include a first oligomerizationstep in which ethylene in an ethylene-containing feedstock from anysource may be converted over a first catalyst at a temperature betweenabout 40° C. and about 220° C. into oligomers that form a firstoligomerization product containing a majority of low-molecular weightolefins with a carbon number between about C4 and about C8. Ethylene inthe ethylene-containing feedstock may be derived from various sourcesincluding, but not limited to, e.g., biomass, cellulose, lignocellulose,starch, natural gas, coal, and petroleum, and methanol- andethanol-containing streams, including combinations of these varioussources. In some applications, low-molecular weight olefins derived fromethylene may include mixtures comprising even carbon number olefins,predominately butenes, hexenes, and octenes, such as 70% C4, 27% C6, and3% C8. In other applications, the ethylene-containing feedstock may alsocontain propylene, such as when the ethylene-containing feed is derivedfrom methanol, and the low-molecular weight olefin mixture willadditionally contain odd-carbon olefins, such as C5, C7, and C9.

A second oligomerization step may convert the first oligomerizationproduct over a second catalyst at a temperature between about 150° C.and about 350° C. to form a second oligomerization product containing amixture of branched open-chain olefins, a selected fraction of whichcomprise fuel-range hydrocarbons and a second fraction comprising secondoligomerization light products boiling below a distillation cut-offpoint. In some embodiments, the second oligomerization product prior toany optional post-processing operations contains between about 0% andabout 4% aromatics by weight.

In some applications, the first oligomerization product may be furthersubjected to one or more processes such as oligomerization orfractionation to obtain olefin products or feedstocks of interest. Forexample, 2-butenes in the first oligomerization product may undergoolefin metathesis with ethylene by known technology to form propene.Propene is a valuable product that may be used for any of a number ofknown industrial processes, such as the production of acrylic acid oracrylonitrile. Propene may also be returned to the secondoligomerization reactor for fuel production. The first oligomerizationproduct may also be used in a separate process step as a feedstock foralkylation of aromatic compounds. For example, in some applications,aromatic hydrocarbons produced from the one-step catalytic conversion ofethanol can be alkylated to form higher molecular weight hydrocarbons,increasing carbon yield in the jet fuel range.

Likewise, in some applications, the second oligomerization product maybe further subjected to one or more optional post-processing operationssuch as fractionation, recycling, aromatization, alkylation, olefinmetathesis, hydrotreatment, and/or other processes to obtain distillatesor fractions containing selected fuel-range hydrocarbons of interest.For example, in some applications the olefinic light products fromfractionation of the second oligomerization can be recycled to thesecond oligomerization reactor inlet for further conversion tofuel-range hydrocarbons. In some applications, the olefinic lightproducts from the second oligomerization can be sent to a reactor forconversion to aromatics. In some applications, these aromatics oraromatic hydrocarbons produced from one-step catalytic conversion ofethanol can also be alkylated with olefinic light products from thesecond oligomerization. In some applications, products from the secondoligomerization may be fractionated, then hydrotreated to form afuel-range hydrocarbons. In some applications, products from the secondoligomerization may be hydrotreated, then fractionated to formfuel-range hydrocarbons.

Hydrotreated distillates from the two-step process may contain variousclasses of hydrocarbons of various molecular masses including, but notlimited to, e.g., paraffins, cycloparaffins, aromatics, and/or otherhydrocarbons. Hydrotreated distillates of the present inventioncontaining fuel-range hydrocarbons may be blended and/or combined invarious ways to produce various renewable hydrocarbon fuels including,but not limited to, e.g., aviation fuels, jet fuels, diesel fuels,gasoline, and/or other hydrocarbon fuels of interest.

The 2-stage system may include a first reactor or reactor stagecontaining a metal catalyst comprising nickel (Ni) supported on acrystalline or amorphous solid aluminosilicate support. The reactor maybe pressurized with a feed gas comprising ethylene that optionallycontains an inert gas such as nitrogen at total pressures selected inthe range from 0 psig to 1200 psig. The first stage reactor may includea feed gas purification system to remove traces of oxygen and water. Thefirst stage reactor may yield a first oligomerization product thatcontains olefins (alkenes) that correspond to successive combinations ofethylene, such as butenes, hexenes, octenes and small amounts of higherolefins with even carbon numbers.

The system may also include a second reactor or second reactor stagethat may be optionally pressurized with a gas such as nitrogen and thatcontains an acid catalyst. The acid catalyst may convert olefins in thefirst oligomerization product from the first reactor stage to form asecond oligomerization product containing fuel-range hydrocarbons. Thefuel-range hydrocarbons may contain larger-chain oligomers with a carbonnumber from about C8 to about C23. Fuel-range hydrocarbons in the secondoligomerization product may include, but are not limited to, e.g.,normal and branched olefins and, depending upon conditions, lowconcentrations of aromatics.

The present invention also includes a process for one-step conversion ofethanol-containing feedstocks to aromatics and other hydrocarbonproducts described herein that can be directly hydrogenated to formcyclic hydrocarbons and/or can be alkylated to obtain higher molecularweight hydrocarbons suitable for production of jet and diesel fuels. Forexample, in some applications, zeolite catalysts may be used to convertethanol to form a “clean” aromatic product containing no appreciablequantity of undesirable durene (1,2,4,5-tetramethylbenzene). Aromaticsmay be alkylated to for higher molecular weight hydrocarbons or may behydrogenated (reduced) to produce oxygen-free cyclic hydrocarbonssuitable for use in production of desired hydrocarbon fuels.

The present invention also includes a one-stage oligomerization systemfor catalytic conversion of ethanol-containing feedstocks that produceolefins (alkenes) and aromatics. Ethanol conversion over zeolitecatalysts, such as HZSM-5, primarily forms diethyl ether throughintermolecular dehydration at temperatures between 175° C. and 250° C.At higher temperatures, for example at about 280° C., intramoleculardehydration forms ethylene. Above about this temperature, ethanol formsethylene and the ethylene undergoes a number of reactions (e.g.,oligomerization, dehydrocyclization, hydrogenation, and cracking) toform a complex mixture of hydrocarbon products (i.e., paraffins,olefins, saturated cyclics, aromatics, and naphthalene), typically witha carbon number between C2 and C12 and with a product distribution thatdepends upon the processing temperature.

The present invention also includes a combined two-step and one-stepoligomerization process and a combined two-stage and one-stageoligomerization system for catalytic conversion of ethylene-containingfeedstocks and ethylene precursor ethanol-containing feedstocks that canbe hydrotreated to produce normal paraffins, iso-paraffinscycloparaffins, indans, tetralins, and alkylated aromatics that may beblended to produce various alternative fuel blend stocks suitable forformation of various hydrocarbon fuels including, e.g., gasolines, jetfuel, and diesel fuel. The combined process and system use theindividual two-step and one-step processes or two-stage and one-stagesystems described above to make blend stocks that can be mixed orblended to make fuels of any desired composition. Thus, in someapplications, combining hydrocarbon products obtained from the two-stepprocess or the two-stage system with products from the one-step processor one-stage system can provide all required compounds necessary toproduce a 100% alternative fuel. Composition of the fuel is determinedby the quantities of each blend stock mixed together.

The purpose of the foregoing abstract is to enable the United StatesPatent and Trademark Office and the public generally, especiallyscientists, engineers, and practitioners in the art who are not familiarwith patent or legal terms or phraseology, to determine the nature andessence of the technical disclosure of the application. The abstract isneither intended to define the invention of the application, which ismeasured by the claims, nor is it intended to be limiting as to thescope of the invention in any way.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exemplary two-step process for conversion of anethylene-containing feedstock into fuel-range hydrocarbons suitable forproduction of alternative (including renewable) hydrocarbon fuels,according to one embodiment of the process of the present invention.

FIG. 2 shows a two-stage system for conversion of ethylene-containingfeedstocks into fuel-range hydrocarbons for production of alternative(including renewable) hydrocarbon fuels.

FIG. 3 shows an exemplary one-step process for conversion of anethanol-containing feedstock into fuel-range hydrocarbons suitable forproduction of alternative (including renewable) hydrocarbon fuels,according to another embodiment of the process of the present invention.

FIG. 4 shows a one-stage system for conversion of ethylene-containingfeedstocks into fuel-range hydrocarbons for production of alternative(including renewable) hydrocarbon fuels.

FIG. 5 shows an exemplary process for a combined one-step/two-stepconversion of ethylene- and ethanol-containing feedstocks intofuel-range hydrocarbons suitable for production of alternative(including renewable) hydrocarbon fuels, according to yet anotherembodiment of the present invention.

FIG. 6 shows an exemplary fuel-blending process for blending fuel-rangehydrocarbons from selected distillates for production of alternative(including renewable) hydrocarbon fuels, according to still yet anotherembodiment of the present invention.

FIGS. 7-20 present selected experimental results.

DETAILED DESCRIPTION

Systems and processes are detailed for catalytic conversion ofethylene-containing and/or ethylene precursor ethanol-containingfeedstocks into fuel-range distillates and fuel-blending feedstocks forproduction of alternative (including renewable) fuels. In the followingdescription, embodiments of the present invention are shown anddescribed by way of illustration of the best mode contemplated forcarrying out the invention. It will be clear that the invention mayinclude various modifications and alternative constructions.Accordingly, the description of the preferred embodiments should be seenas illustrative only and not limiting. The present invention includesall modifications, alternative constructions, and equivalents fallingwithin the spirit and scope of the invention as defined in the claims. Acontrolled 2-step/2-stage oligomerization will now be described thatproduces primarily normal and isoparaffin hydrocarbons, forms minimalaromatics, has high carbon efficiency in the distillate range(especially for jet and diesel fuels), minimizes formation ofnaptha-like components, and allows efficient intermediate productrecycling as one means to increase product yield in the distillaterange.

Two-Step Oligomerization Process

FIG. 1 shows an exemplary two-step oligomerization process for catalyticconversion of ethylene-containing feedstocks that, in the preferred modeof operation, yields fuel-range hydrocarbon distillates containingopen-chain oligomers at a high selectivity (>96%) including, e.g.,normal paraffins and isoparaffins. Fuel-range distillates have a lowconcentration of aromatics (<4 wt %) that renders these distillatesideally suited to production of alternative (including renewable)hydrocarbon fuels such as jet fuels and diesel fuels, or other lowaromatic fuels and fuel blend stocks. In other modes of operation,concentrations of aromatics >4% may be obtained. As shown in the figure,ethylene in the ethylene-containing feedstock may be derived from suchfossil fuel sources such as petroleum, coal, and natural gas. Ethylenemay also be obtained from bio-based sources and/or alternative sourcesincluding, but not limited to, e.g., sugars and sugar derivatives suchas ethanol, starches and starch derivatives such as starch ethanol, andlignocellulose and lignocellulosic derivatives such as lignocellulosicethanol.

Ethanol as an Ethylene Source

Ethylene used in ethylene-containing feedstocks in the firstoligomerization step/stage may be derived from ethanol. Ethanol may bederived from any known thermal or biological process. Pure ethanol isnot required. For example, in some applications, aqueous ethanol may beused to lower production costs. In some applications, concentrations ofethanol of about 50% or greater ethanol in water may be used. In someapplications, the source of aqueous ethanol may be obtained from afermentation purified via a “Beer Column” distillation. In someapplications, the concentration of ethanol may be between 20% and 100%.

Ethanol or ethanol-containing feedstocks may be optionally fed to adehydration reactor optionally with an inert gas such as N₂, pre-heatedto a selected reaction temperature, and passed over a dehydrationcatalyst (e.g., alumina, modified alumina, silicoaluminate, modifiedsilicoaluminate, and other catalysts) at a temperature and pressuresufficient to carry out the dehydration reaction that forms ethylene.Conditions depend on the catalyst used, which may be determined usingmethods known to those of ordinary skill in the art. This process ispracticed industrially. No limitations are intended.

In various embodiments, ethanol may be introduced to the dehydrationreactor at a weight hourly space velocity (WHSV) of between about 0.1h⁻¹ to about 30 h⁻¹. In some embodiments, ethanol may be fed to thedehydration reactor at a WHSV value of between about 0.5 h⁻¹ to about 5h⁻¹.

In some embodiments, the dehydration reactor may be operated at atemperature from about 200° C. to about 500° C. In some embodiments, thedehydration reactor may be operated at a temperature from about 300° C.to about 450° C. In some embodiments, the dehydration reactor may beoperated at a pressure from about 0 psig to about 1200 psig. In someembodiments, the dehydration reactor may be operated at a pressure fromabout 0 psig to about 500 psig.

Ethanol conversion may vary depending on operating conditions and theselected catalyst from between about 10% and about 100%.

The ethylene-containing product may be purified to remove water,by-products, oxygen, and other impurities. Purification could includecondensing water and purifying the product through a purifying mediumsuch as silicas, molecular sieves, and carbons. The purified product maybe collected or passed directly to the first oligomerization reactor.

Mixed alcohols with a carbon number from C1 to C4 and greater can beprepared from syngas over any of several catalysts. Certain catalysts,such as those containing rhodium, are selective for ethanol. Others,such as Co/Mo/sulfide, have higher selectivity to methanol, but onrecycle of the methanol selectivity to ethanol increases. Mixed alcoholscontaining ethanol are easily dehydrated by methods discussed above toform an ethylene-containing feed for the two-step process or two-stagesystem.

Methanol as an Ethylene Source

The process for conversion of methanol to olefins (MTO) can be used toform mixtures of predominately ethylene and propylene at high yields.Selectivities to C2 to C4 olefins of 96% have been reported. MTO can bea source of ethylene-containing feed for the two-step process ortwo-stage system. Methanol for this process could be obtained from anysource, the major source being from syngas.

1^(st) Oligomerization Process C2 to Oligs

Ethylene or an ethylene-containing feed from any source may be fed to afirst oligomerization reactor or group of reactors, optionally with aninert gas such as N₂, pre-heated to selected reaction temperatures, andpassed over a first oligomerization catalyst (e.g., nickel on asilicoaluminate material support) at selected temperatures and pressuresto carry out the first oligomerization step of a two-step process.Gaseous feeds may be passed through purifying media such as silicasand/or molecular sieves to remove trace water and copper-based and othermaterials to remove trace oxygen.

In various embodiments, ethylene in the ethylene-containing feedstockmay be introduced to the first oligomerization reactor at a weighthourly space velocity (WHSV) of between about 0.1 h⁻¹ to about 100 h⁻¹.In various embodiments, ethylene in the ethylene-containing feedstockmay be introduced to the first oligomerization reactor at a WHSV valueof between about 0.5 h⁻¹ to about 5 h⁻¹.

In some embodiments, first oligomerization reactor may be operated at atemperature from about 40° C. to about 220° C. In some embodiments,first oligomerization reactor may be operated at a temperature fromabout 80° C. to about 160° C. In some embodiments, first oligomerizationreactor may be operated at a pressure from about 0 psig to about 1200psig. In some embodiments, first oligomerization reactor may be operatedat a pressure from about 100 psig to about 500 psig.

First oligomerization products may include light oligomers, and mixturesof intermediate molecular weight normal and branched olefins. Carbonnumber may be primarily from about C4 to about C8. In one embodiment,the hydrocarbon product may include 70% C4, 27% C6, and 3% C8hydrocarbons including, e.g., butenes, hexenes, and octenes. Hydrocarbonproducts may be collected or passed directly to the secondoligomerization step of the two-step process.

The first oligomerization step may be conducted in one reactor, inmultiple sequential reactors, and/or in parallel reactors. Multiplereactors can be used, for example, to manage process heat. Conversion ofethylene in each reactor varies with operating conditions from betweenabout 10% conversion to about 100% conversion. Ethylene may be recycledto any of the reactors to increase overall conversion.

2^(nd) Oligomerization Process

Oligomers in the first oligomerization product may be converted in asecond oligomerization step of the two-step process over selected solidacid catalysts to mixtures of higher molecular weight oligomersincluding, e.g., branched open-chain olefins with a carbon number in thedistillate range from about C8 to about C23. Solid acid catalystsinclude, but are not limited to, e.g., crystalline zeolite catalysts,amorphous silicoaluminate catalysts, acid form cation exchange resins,such as Amberlyst 70, and other acid catalysts. In some embodiments,aromatic hydrocarbons may be formed at a concentration below about 4 wt%. In some embodiments, aromatic hydrocarbons may be formed at aconcentration between 4 and 10%. In some embodiments, aromatichydrocarbons may be formed at a concentration between 10 and 20%.However, concentration of aromatics can be tailored to any desiredconcentration under appropriate conditions. Temperatures may be selectedthat are sufficiently high to initiate and promote oligomerizationreactions but sufficiently low to minimize and avoid coking, and tominimize aromatization. In some embodiments, temperatures are selectedbetween about 150° C. to about 350° C. In some embodiments, temperaturesare selected between about 200° C. to about 280° C.

In some embodiments, the second oligomerization reactor may be operatedat a pressure from about 50 psig to about 1000 psig. In someembodiments, the second oligomerization reactor may be operated at apressure from about 100 psig to about 500 psig. In various embodiments,the first oligomerization product may be introduced to the secondoligomerization reactor at a weight hourly space velocity (WHSV) ofbetween about 0.1 h⁻¹ to about 100 h⁻¹. In various embodiments, thefirst oligomerization product may be fed to the second oligomerizationreactor at a WHSV value of between about 0.5 h⁻¹ to about 10 h⁻¹. Insome embodiments, the second oligomerization product may be processed inpost-processing steps described below. No limitations are intended.

Two-Stage Oligomerization System

FIG. 2 shows an exemplary reactor system of a two-stage oligomerizationdesign for catalytic conversion of ethylene-containing feedstocks or anethylene precursor feedstock such as ethanol (or ethanol-containingfeedstocks) into fuel-range hydrocarbons suitable for production ofalternative hydrocarbon fuels. Each reactor or stage may be charged witha selected catalyst.

[Ethanol Conversion] The system may include a dehydration reactor as afirst stage when ethanol-containing feedstocks are used as an ethyleneprecursor. Dehydration reactor may be charged with a solid aciddehydration catalyst such as alumina, modified alumina, crystalline oramorphous silicoaluminate, modified silicoaluminate, and othercatalysts. The ethanol-containing feedstock may be introduced intodehydration reactor as a liquid feed at a WHSV value of between about0.1 h⁻¹ and about 30 h⁻¹. Dehydration reactor may be operated at adehydration temperature of about 200° C. to about 500° C. and a pressureof between about 0 psig to about 1200 psig. Ethanol concentrations maybe in the range of 20 to 100 wt %. Preferred conditions are dependent onthe catalyst and size of the reactor and are known to those skilled inthe art. For the purposes of demonstrating this invention, a preferredWHSV is 0.5 h⁻¹ to 5 h⁻¹, a preferred temperature is 300° C. to 450° C.,and a preferred pressure is 0 psig to 500 psig. Dehydration reactor mayyield a mixed phase product containing predominately gaseous ethyleneand a liquid waste water phase.

The ethylene-containing product obtained from dehydration reactor mayrequire several cleanup steps performed in separate reactors or stagesprior to being introduced to first oligomerization reactor or stagedescribed hereafter. Clean-up steps may include a condensation stepperformed in a condensation stage (not shown) to remove liquids andadsorbent stages that remove trace water, organics, and oxygenimpurities. Purified ethylene produced by this system is theethylene-containing feedstock that feeds the first oligomerizationsystem.

[First oligomerization] The system may also include a firstoligomerization reactor or stage. Ethylene-containing feedstock, such asthat obtained from dehydration reactor, may be introduced to firstoligomerization reactor. First oligomerization reactor may be chargedwith a selected oligomerization catalyst such as Ni on asilicoaluminate. Ethylene-containing feedstock may be introduced, e.g.,as a gas feed into first oligomerization reactor at a WHSV value ofbetween 0.1 h⁻¹ to about 100 h⁻¹. First oligomerization reactor may beoperated at a temperature of between about 40° C. and 220° C. and apressure of between 0 psig and about 1200 psig. A preferred temperatureis from about 80° C. to about 160° C. A preferred pressure is from about100 psig to about 500 psig. A preferred WHSV is from about 0.5 h⁻¹ toabout 5 h⁻¹. First oligomerization reactor or stage may yield a firstoligomerization product containing predominately C4, C6, and C8oligomerization products.

In some embodiments, one or more reactors may be operated as firstoligomerization reactors in series and/or in parallel, each operated,for example, at a lower conversion rate to control exotherms, butconfigured to provide high overall ethylene conversion.

In some embodiments, ethanol dehydration and first oligomerization maybe operated independently or operated as integrated flow reactors.

In some embodiments, residual liquids may be removed from the firstoligomerization product in a liquid/gas (L/G) separator (not shown)prior to being introduced in a feed to second oligomerization stage.

[Second oligomerization] The system may also include a secondoligomerization reactor or stage. Second oligomerization reactor orstage may be charged with a second oligomerization catalyst such as asolid acid including, e.g., a crystalline or amorphous silicoaluminatedescribed previously herein. First oligomerization product obtained fromfirst oligomerization reactor or stage may be introduced to secondoligomerization reactor or stage. Second oligomerization reactor orstage may be operated at a WHSV of between 0.1 h⁻¹ and 100 h⁻¹, atemperature of between about 150° C. and about 350° C., and a pressureof between 50 psig and about 1000 psig. A preferred condition is a WHSVof about 0.5 h⁻¹ and 10 h⁻¹, a temperature of 200° C. to 280° C., and apressure of from about 100 psig to about 500 psig. In operation, firstoligomerization product may be pre-heated to a vapor, e.g., at atemperature of about 200° C. to about 280° C.

Second oligomerization reactor or stage may yield a secondoligomerization product containing olefinic fuel-range hydrocarbons.Reactions are exothermic. Heat obtained in second oligomerizationreactor or stage may be collected for use in pre-heating the feed, orelsewhere. In some embodiments, the second stage product may be furtherprocessed in post-processing stages, described below. No limitations areintended.

Post-Processing

Oligomers (about C4 to about C23) obtained from the two-step process ortwo-stage system may be subjected to optional post-processing processsteps or system stages including, e.g., fractionation, recycling,aromatization, alkylation, olefin metathesis, and/or hydrotreatmentdescribed further hereafter. Other post-processing operations may alsobe used and no limitations are intended.

Fractionation

Hydrocarbon products obtained from the second oligomerization reactormay include linear and branched olefin hydrocarbons with a carbon numberfrom about C4 to about C23. Fractionation, e.g., by distillation or byflash evaporation, may be conducted at a determined fractionationtemperature or boiling point cut-off to separate out various boilingpoint fractions appropriate to a desired fuel product and to collectolefinic light products for further processing. Fractionation may beconducted as a process step or in a selected system stage.

In some embodiments, fractionation may be conducted prior tohydrogenation to form light olefin distillates and olefin heavy productsthat can be processed further independently.

The light fraction may be recycled to the first or secondoligomerization step or stage for conversion to hydrocarbon fuels,thereby increasing yield to products in the distillate range. The lightfraction may be sent to a third reactor for conversion to aromatichydrocarbons, which may in turn be used for fuel blending orhydrogenated to afford a cyclic paraffin blend stock. The light fractioncould be combined with an aromatic-containing process stream to alkylatethe aromatics to a higher-boiling product, which may in turn be used forfuel blending or hydrogenated to afford a cyclic paraffin blend stock.Light fractions can be reformed to generate hydrogen gas forhydrotreating operations. Light fractions can be used as a feed to anolefin metathesis reactor to make other olefin products. Distillateolefin fractions can be in any or all of the jet, diesel, or other fuelranges. Fractions can be hydrogenated to provide paraffin andiso-paraffin fuels or fuel blend stocks. Heavy olefin fractions boilingabove a desired fuel range can be cracked over selected catalysts toproduce lower boiling fractions. Heavy fractions containing olefins maybe passed with ethylene over a metathesis catalyst such as atungsten-based or molybdenum-based catalyst to form lower molecularweight olefinic fuel-range hydrocarbon products that can be recycled orfractionated to produce fuel products as described herein.

In another embodiment, fractionation can be conducted upon completion ofall other post-processing in order to more accurately control thecomposition of the collected fractions. Such control might be desirable,for example, if a specific boiling point range were desired to meet thespecifications of a desired fuel type.

Recycling

Recycling can be performed as a process step or in a selected systemstage. For example, unreacted ethylene and/or a light fraction may berecycled back to either the first or second oligomerization steps orstages to increase carbon number and product yield in the desireddistillate range. For example, light products from fractionation ofsecond oligomerization product may be recycled by combining a quantitybetween 0% and 100% with first oligomerization reactor product to make anew feed that can then be introduced to the second oligomerizationreactor. Fuel-range hydrocarbons obtained from oligomerization ofrecycled light fraction hydrocarbons may include, but are not limitedto, e.g., a majority composition of linear and branched C8 to C23olefins and a minor composition of aromatics. For example, the presentinvention produces C8 and greater carbon-number products at aselectivity greater than or equal to about 75% by weight on average andC10 and greater carbon-number products at a selectivity greater than orequal to about 55% by weight on average. Selectivity values after onerecycle of the light fraction from the second oligomerization are ≥C8 ofabout 90% and ≥C10 of about 70%. Aromatics are formed at ≤4%. Additionalrecycling will further increase selectivity to the desired carbon numberor boiling point range. Second oligomerization products obtained fromrecycled materials may be subjected to any post-processing method. Nolimitations are intended.

Aromatization

Light olefins obtained from fractionation of the second oligomerizationhydrocarbon product may be fed to a reactor for conversion to aromaticcompounds. Aromatic compounds may be used directly as fuels, in fuelblend stocks, and/or as fuel precursors. Light olefins may be fed to areactor optionally with an inert gas such as N₂, pre-heated to selectedreaction temperatures, and passed over selected aromatization catalystsat temperatures and pressures sufficient to carry out aromatization.Aromatization catalysts employed in the reactor may include, but are notlimited to, zeolites such as H-ZSM-5, or metal-exchanged zeolites suchas potassium exchanged H-ZSM-5. No limitations are intended.Aromatization operation can be conducted as a process step or in aselected system stage.

In various embodiments, feed may be introduced to the aromatizationreactor at a WHSV of between about 0.1 h⁻¹ to about 100 h⁻¹. In someembodiments, feed may be introduced to the aromatization reactor at aWHSV value of between about 0.5 h⁻¹ to about 5 h⁻¹.

In some embodiments, the aromatization reactor may be operated at atemperature selected between about 250° C. and about 500° C. In someembodiments, the aromatization reactor may be operated at a temperatureselected between about 300° C. and about 400° C. In some embodiments,the aromatization reactor may be operated at a pressure selected betweenabout 0 psig and about 1000 psig. In some embodiments, the aromatizationreactor may be operated at a pressure between about 50 psig and about500 psig.

Alkylation

Aromatic products, obtained for example from the aromatization reactor,the one-step product, or any other sources, may be mixed with analkylating olefin stream, comprising ethylene, first oligomerizationproducts, or olefinic light products from fractionation of the secondoligomerization product, and introduced to an alkylation reactor toincrease the molecular weight of the aromatic products in order toincrease yield in a desired distillate range. Alkylated aromaticcompounds so obtained may be used directly as fuels, in fuel blendstocks, and/or as fuel precursors, before or after fractionation and/orhydrotreating. Feedstock conversion varies with operating conditionsbetween about 10 to about 100%.

Aromatic products and alkylating olefins may be fed to a reactoroptionally with an inert gas such as N₂, pre-heated to selected reactiontemperatures, and passed over selected alkylation catalysts attemperatures and pressures sufficient to carry out alkylation.Alkylation catalysts employed in the reactor may include, but are notlimited to, strong acid catalysts, such as zeolites including H-ZSM-5 orBeta zeolite. Alkylation operation can be conducted as a process step orin a selected system stage.

In various embodiments, feed may be introduced to the alkylation reactorat a WHSV of between about 0.1 h⁻¹ to about 100 h⁻¹. In someembodiments, feed may be introduced to the alkylation reactor at a WHSVvalue of between about 0.5 h⁻¹ to about 5 h⁻¹.

In some embodiments, the alkylation reactor may be operated at atemperature selected between about 50° C. and about 500° C. In someembodiments, the alkylation reactor may be operated at a temperatureselected between about 100° C. and about 350° C. In some embodiments,the alkylation reactor may be operated at a pressure selected betweenabout 50 psig and about 2500 psig. In some embodiments, the alkylationreactor may be operated at a pressure between about 200 psig and about600 psig.

Olefin Metathesis

Light or heavy olefin products obtained from fractionation ofhydrocarbon products from the second oligomerization step or stage maybe co-fed with ethylene to a reactor containing an olefin metathesiscatalyst for conversion to shorter-chain alpha-olefins. Olefinmetathesis catalysts include, but are not limited to, W or Mo onalumina. Metathesis reactions fragment and/or redistribute carbon-carbondouble bonds in the olefins. For example, olefin products may be fed tothe metathesis reactor with ethylene and optionally with an inert gassuch as N₂, pre-heated to reaction temperature, and passed over themetathesis catalyst at a temperature and pressure sufficient to carryout the metathesis reactions that yield lighter olefin products. Thisoperation can be conducted as a process step or system stage.

In various embodiments, feed may be introduced to the metathesis reactorat a WHSV of between about 0.1 h⁻¹ to about 100 h⁻¹. In someembodiments, feed may be introduced to the metathesis reactor at a WHSVvalue of between about 0.5 h⁻¹ and about 5 h⁻¹.

In some embodiments, metathesis reactor may be operated at a temperatureselected from about 50° C. to about 500° C. In some embodiments,metathesis reactor may be operated at a temperature selected from about100° C. to about 350° C.

In some embodiments, metathesis reactor may be operated at a pressureselected from about 50 psig to about 1000 psig. In some embodiments,metathesis reactor may be operated at a pressure from about 100 psig toabout 500 psig.

Hydrocarbon products may be collected and further fractionated to obtaindesired fuel-range hydrocarbons. Feedstock conversion varies withoperating conditions between about 10% and about 100%.

Hydrotreatment

Hydrocarbon products from the second oligomerization step, fractions ofthose products, or products from other post-processing operations may beintroduced as feeds to a hydrotreater and converted to saturatedhydrocarbon fuels and fuel blend stocks. Hydrocarbon product feeds maybe introduced to the hydrotreater optionally with an inert gas such asN₂ at selected feed rates, pre-heated to a selected reactiontemperature, and passed over a catalyst at a temperature and pressuresufficient to carry out hydrogenation. Hydrogenation catalysts employedin the hydrotreater may include, but are not limited to, Pt on alumina,Pt on carbon, Ni on silica, and Raney-type catalysts including, but notlimited to Raney Ni. Choice of catalyst depends, in part, on whether itis desirable to hydrogenate olefins (Pt) or both olefins and aromatics(Ni). Hydrotreating operation may be conducted as a process step or in aselected system stage.

In various embodiments, feed may be introduced to the hydrotreater at aWHSV of between about 0.1 h⁻¹ to about 100 h⁻¹. In some embodiments,feed may be introduced to the hydrotreater at a WHSV value of betweenabout 0.5 h⁻¹ to about 10 h⁻¹.

In some embodiments, the hydrotreater may be operated at a temperatureselected between about 100° C. and about 400° C. In some embodiments,the hydrotreater may be operated at a temperature selected between about150° C. and about 350° C. In some embodiments, the hydrotreater may beoperated at a pressure selected between about 100 psig and about 2000psig. In some embodiments, the hydrotreater may be operated at apressure between about 500 and about 1000 psig. Hydrotreater productsmay be collected or further fractionated to obtain a desired fuel suchas jet, diesel, or gasoline or a fuel blend stock product. Feedstockconversion varies with operating conditions between about 10% and about100%.

Reactors

Reactors may be of any type that provides contact between the selectedfeed or feedstock and the selected catalyst. In some embodiments,reactors may be of a fixed-bed type, but reactors are not intended to belimited. Reactors suitable for use include, but are not limited to,e.g., fixed-bed reactors, fluidized bed reactors, circulating fluid-bedreactors, batch reactors, flow reactors, sequential flow reactors,continuous stirred-tank reactors, sequential continuous stirred-tankreactors, batch-flow reactors, ebulated-bed reactors, packed-bedreactors, tubular reactors, multi-tubular reactors, sequentialmultitubular reactors, network reactors, heat-exchange reactors,gas-liquid reactors, gas-solid reactors, radial-flow reactors,reverse-flow reactors, ring reactors, moving bed reactors, catalyticreactors, chemical reactors, gas reactors, trickle-bed reactors, columnreactors, batch reactors, N-dimensional reactors and N-phase reactorswhere N is a number of dimensions or phases, heated reactors, cooledreactors, including combinations and components of these variousreactors.

The two-step process or two-stage system may be performed in concertwith other processes or systems to produce alternate fuels notobtainable by other methods. One such process or system will now bedescribed.

One-Step Oligomerization

FIG. 3 illustrates an exemplary one-step oligomerization process forcatalytic conversion of ethanol-containing feedstocks that producesolefins (alkenes) and aromatics and other hydrocarbon products. Ethanolconversion over zeolite catalysts, such as HZSM-5, forms primarilydiethyl ether through intermolecular dehydration at temperatures between175° C. and 250° C. At higher temperatures of about 280° C.,intramolecular dehydration forms ethylene. Above temperatures of 280°C., ethanol forms ethylene and ethylene undergoes reactions including,e.g., oligomerization, dehydrocyclization, hydrogenation, and crackingthat form complex mixtures of hydrocarbon products including, e.g.,paraffins, olefins, saturated cyclics, aromatics, and naphthalene withtypical carbon numbers between C2 and C12. Product distribution dependson processing temperatures and catalyst. In some embodiments, zeolitecatalysts may be used to convert ethanol to form a “clean” aromaticproduct containing no appreciable quantity of undesirable durene(1,2,4,5-tetramethylbenzene). In some embodiments, aromatics may bealkylated to form higher molecular weight hydrocarbons or may behydrogenated (reduced) to produce oxygen-free cyclic hydrocarbonssuitable for use in production of desired hydrocarbon fuels.

In some embodiments, temperatures are selected between about 280° C. toabout 500° C. In some embodiments, temperatures are selected betweenabout 300° C. to about 450° C. In some embodiments, the one-step reactormay be operated at a pressure from about 0 psig to about 1000 psig. Insome embodiments, the one-step reactor may be operated at a pressurefrom about 50 psig to about 500 psig. In various embodiments, theethanol-containing feed may be introduced to the one-step reactor at aWHSV of between about 0.1 h⁻¹ to about 100 h⁻¹. In various embodiments,the ethanol-containing feed may be introduced to the one-step reactor ata WHSV of between about 0.5 h⁻¹ to about 10 h⁻¹. In some embodiments,the one-step oligomerization product may be processed in post-processingsteps described above. No limitations are intended.

One-Stage Oligomerization System

FIG. 4 shows an exemplary reactor system of a one-stage oligomerizationsystem for catalytic conversion of ethanol feedstock into olefins(alkenes) and aromatics suitable for production of alternativehydrocarbon fuels and fuel blend stocks. The dehydration/oligomerizationreactor stage may be charged with a selected catalyst well known in theart. The catalyst could be silicoaluminates, silicoaluminophosphates,heteropoly acids, or others. Catalysts may be crystalline or amorphous.

In some embodiments, temperatures are selected between about 280° C. toabout 500° C. In some embodiments, temperatures are selected betweenabout 300° C. to about 450° C. In some embodiments, the one-step reactormay be operated at a pressure from about 0 psig to about 1000 psig. Insome embodiments, the one-stage reactor may be operated at a pressurefrom about 50 psig to about 500 psig. In various embodiments, theethanol-containing feed may be introduced to the one-stage reactor at aWHSV of between about 0.1 h⁻¹ to about 100 h⁻¹. In various embodiments,the ethanol-containing feed may be introduced to the one-stage reactorat a WHSV of between about 0.5 h⁻¹ to about 10 h⁻¹. In some embodiments,the one-stage oligomerization product may be processed inpost-processing stages described above. No limitations are intended.

Dehydration/oligomerization stage may yield a mixed phase productcontaining predominately an organic liquid product phase and a liquidwaste water phase. Optional post-processing stages can be conducted,including fractionation, alkylation, hydrogenation, and others asdescribed above. No limitations are intended.

Combined Two-Step and One-Step Oligomerization

FIG. 5 shows another exemplary process of the present invention thatcombines 2-step oligomerization processing for catalytic conversion ofethylene-containing feedstocks or feedstocks containing an ethyleneprecursor such as ethanol, and 1-step oligomerization processing forcatalytic conversion of ethanol-containing feedstocks. The combinedprocess yields distillates suitable for production of alternativehydrocarbon fuels. The combined process produces fuels and fuel blendstocks not available from either process independently nor from otherprocesses known in the art. Likewise, the one-stage system may becombined with the two-stage system to define a combined system thatproduces fuels and fuel blend stocks not available from either systemindependently nor from other systems known in the art.

Ethylene-containing feeds and ethanol-containing feeds may be obtainedfrom various sources detailed previously herein. Ethanol-containingfeedstocks may be fed directly to a 1-step oligomerization system orprocess that converts the feedstock at selected temperatures andpressures to a complicated product mixture containing a majorityaromatic products, naphthalenes, saturated cyclics, paraffins, andolefins. A majority of products may include carbon numbers between aboutC2 to about C12. The 1-step oligomerization system and process andoptional post-processing are discussed in more detail above.

As another part of the present invention, ethylene-containing feeds maybe fed to a two-step oligomerization system or process that converts thefeedstock at selected temperatures and pressures to a product mixturecontaining normal and iso-paraffins. A majority of products may includecarbon numbers between about C4 to about C23. The two-stepoligomerization process and system and optional post-processing werediscussed previously above.

As shown in the figure, products obtained from one-step processing,including optional post-processing steps, may be blended with productsobtained from the two-step oligomerization, including optionalpost-processing steps, to form blended products. Blended products mayform an alternative fuel or fuel feedstock suitable for production ofvarious fuels including, but not limited to, e.g., gasoline, jet fuel,and diesel fuel. In one embodiment, optional hydrogenation may beconducted prior to blending. In other embodiments, optionalhydrogenation may be conducted after blending. In other embodiments,optional fractionation may be conducted prior to blending. In yet otherembodiments, fractionation may be conducted after blending. Nolimitations are intended.

Fuel Blending of Two-Step and One-Step Oligomerization Products

FIG. 6 shows an exemplary process for blending products obtained fromtwo-step oligomerization processing and one-step oligomerizationprocessing (FIG. 3) described previously hereinabove. As shown in thefigure, one-step products and two-step products may be blended,fractionated, and hydrotreated. Or, one-step products and two-stepproducts may be separately or individually fractionated andhydrotreated, and then blended. Hydrocarbon products may also be blendedin various ways to produce various alternative fuels including, but notlimited to, e.g., gasoline, jet fuel, and diesel fuel.

For example, two-step oligomerization products may include normal andbranched olefins that when hydrotreated with hydrogen at selectedtemperatures and hydrogen gas pressures form paraffins including,n-paraffins and i-paraffins. One-step oligomerization products mayinclude primarily olefins and aromatic hydrocarbons that whenhydrotreated at selected temperatures and hydrogen gas pressures formcycloparaffins, indans, and tetralins. Aromatic content may becontrolled by the extent or degree of hydrogenation of one-stepproducts.

In some embodiments, light olefin products from two-step processing maybe combined with aromatics from one-step processing to produce alkylatedaromatics with a molecular weight higher than the feed aromatics and anincreased yield in the desired fuel range.

In yet other embodiments, the light olefins outside the desired fuelrange can be sent to an aromatization reactor to produce aromatics thatcould be combined with one-step products or subjected to furtherprocessing, including fuel blending, alkylation, or hydrotreating.

Hydrotreated product materials may be blended in selected ratios toproduce desired fuels. Choice of processing options depends at least inpart on the desired composition of the fuels to be produced. As shown inthe figure, products obtained from one-step oligomerization and two-stepoligomerization following further optional processing as described andhydrotreating may be blended in various ways to produce variousalternative fuels including, but not limited to, e.g., gasoline, jetfuel, and diesel fuel.

Catalysts

[Ethanol Dehydration Catalyst]

Dehydration catalysts that convert ethanol to ethylene include, but arenot limited to, e.g., silicoaluminate catalysts, aluminas, modifiedaluminas, and other solid acid catalysts. Alumina-based materialsinclude BASF AI 3992 E ⅛″. Silicoaluminate catalysts may have acrystalline structure such as beta zeolite, H-ZSM-5, and like materials.Silicoaluminate catalysts may also have an amorphous structure such asGrace 3111 and like materials. Silicoaluminate catalysts may be in theform of a powder (e.g., Grace 3111 and similar materials), or have anengineered form (e.g., Grace Davicat X-501 and similar materials).Silicoaluminate catalysts may be commercially obtained. Silicoaluminatecatalysts may also be prepared from suitable Si-containing andAl-containing materials by methods known in the catalyst art. Preparedsilicoaluminate catalysts may be calcined at temperatures between about200° C. and about 900° C.

[First Oligomerization Catalyst].

A preferred catalyst for first step oligomerization may be nickel on asilicoaluminate material support. In some embodiments, nickel (Ni)concentration in the catalyst may be selected in the range from about0.1 wt % to about 10 wt %. In some embodiments, nickel (Ni)concentration in the catalyst may be preferably selected in the rangefrom about 0.2 wt % to about 3 wt %.

Silicoaluminate support may have a crystalline structure such as betazeolite and like materials. Silicoaluminate support may also have anamorphous structure such as Grace 3111 and like materials. Support maybe in the form of a powder (e.g., Grace 3111 and similar materials), orhave an engineered form (e.g., Grace Davicat X501 and similarmaterials). Support may be commercially obtained or may be prepared fromsuitable Si-containing and Al-containing materials, such as sodiumsilicate and alumina and their precursors by such methods as sol-gelsynthesis.

Catalyst supports may be calcined at a temperature between about 200° C.and about 900° C. In some embodiments, nickel may be incorporated intothe catalyst support by batch or column ion exchange, impregnation, orsimilar methods before or after calcination. In some embodiments, thecatalyst support may be ion-exchanged with a Group I or Group II saltsuch as sodium chloride or sodium nitrate before or after calcination.In some embodiments, the catalyst support may be treated with a Group Ior Group II base such as sodium carbonate or sodium acetate to reduce oreliminate Brønsted acidity before or after calcination. Nickel may beincorporated into the catalyst support by batch or column ion exchange,impregnation, or similar methods before or after treatment with a GroupI or II salt or base and before or after calcination. In someembodiments, the catalyst support may be treated with ammoniumhydroxide, washed, and dried before nickel is incorporated by anymethod.

[Second Oligomerization Catalyst]

Catalysts for second stage oligomerization may be silicoaluminatecatalysts or may be solid acid catalysts like Amberlyst 70.Silicoaluminate catalysts may have a crystalline structure such as betazeolite, H-ZSM-5, and like materials. Silicoaluminate catalysts may alsohave an amorphous structure. Silicoaluminate catalysts may also be inthe form of powders (e.g., Grace 3111 and similar materials), or have anengineered form (e.g., Grace Davicat X-501 and similar materials).Silicoaluminate catalysts may be commercially obtained. Silicoaluminatecatalysts may also be prepared from suitable Si-containing andAl-containing materials by methods known to those of ordinary skill inthe art. Prepared silicoaluminate catalysts may be calcined attemperatures between about 200° C. and about 900° C.

In some embodiments, the second oligomerization catalyst may includeacid zeolites including, e.g., Y-zeolites, Beta-zeolites, ZSM-5 zeolites(e.g., H-ZSM-5), Mordenite zeolites, Ferrierite zeolites, AI-MCM-41zeolites, MCM-48 zeolites, MCM-22 zeolites, SAPO-34 zeolites, Chabazitezeolites, and combinations of these acid zeolites.

In some embodiments, the solid acid may include a concentration of anacidic metal oxide and/or an acid zeolite of between about 10% and about80% by weight.

[Aromatization Catalysts]

Aromatization catalysts employed in the reactor may include, but are notlimited to solid acid catalysts, e.g., crystalline zeolites, or theirion-exchanged derivatives. In some embodiments, the aromatizationcatalyst may be a partially potassium-exchanged H-ZSM-5.

[Hydrogenation Catalyst]

Hydrogenation catalysts suitable for hydrotreating selected feeds mayinclude, but are not limited to, e.g., metals supported on various solidsupports. Catalyst metals include, but are not limited to, e.g.,ruthenium (Ru), rhenium (Re), palladium (Pd), platinum (Pt), nickel(Ni), and combinations of these metals. Preferred metal supports includebut are not limited to, e.g., carbon, titania (TiO₂), zirconia (ZrO₂),alumina (Al₂O₃), and silica (SiO₂). Solid supports may be impregnatedwith the selected metal by contacting the solid oxides with an aqueoussolution containing the selected metal salt. Once impregnated, metalions in solution may be reduced at a temperature of, e.g., 300° C. inhydrogen gas, which activates the catalyst for use. For supported-metalcatalysts, metal concentrations may be from about 0.5% to about 10% byweight. Metal support concentrations may be between about 90% and about99.5% by weight. Catalysts may be of the Raney type, including but notlimited to Raney nickel.

In some embodiments, hydrogenation catalysts include, e.g., platinum oncarbon, platinum on alumina, and nickel on silica.

In some embodiments, hydrogenation catalysts may includesulfide-containing (i.e., sulfided) catalysts or non-sulfide-containing(i.e., non-sulfided) catalysts.

[Olefin Metathesis]

Olefin metathesis catalysts include, but are not limited to, e.g., W orMo on alumina.

Catalysts of the present invention may be regenerated in the presence ofoxygen to remove any coke formed on the catalysts during operation byoxidation.

Applications

The present invention finds application in private, commercial, andmilitary aviation and private, commercial, and military landtransportation. Integration of processes allows production of higherrenewable content fuels, with benefits for co-location on a single sitesuch as infrastructure, utilities, heat and energy balance, and hydrogenproduction.

EXAMPLES

The following Examples provide a further understanding of the invention:

Example 1 Preparation of First Oligomeriation Catalyst

2.96 g of boehmite-alumina powder (e.g., Catalog #23N4-80 DISPAL®boehmite-alumina powder, Sasol Ltd., Houston, Tex., USA) was mixed with5.0 g of solid NaOH pellets with enough deionized water to make a 250 mLsolution. The solution was stirred and heated to 50-70° C. for 2.5 hruntil solids were dissolved. The hot solution was rapidly added to amixture of 300.05 g of sodium silicate solution (e.g., 26 wt % SiO₂,Sigma-Aldrich, St. Louis, Mo., USA) and 1085.15 g of deionized water andstirred for about 5 minutes. 430 mL of a 1.4 M nitric acid solution wasthen added, which formed a gel. The gel was stirred at room temperaturefor 3 days to age the gel. The aged gel was then separated from thesupernatant via centrifugation. Centrifuged solids were re-slurried inabout 1.5 L of deionized water, heated to 60-70° C., and agitated for atleast 1.5 hr. The centrifugation, re-slurry, and agitation cycle wasrepeated three more times. The gel was then washed in a Buchner filteruntil the wash water attained a pH of 7. The gel was dried overnight inthe Buchner filter in a flow of air, then heated in air in a porcelaincrucible from room temperature to 110° C. at a rate of 5° C./min. Thedried gel was then held for 3 hours at 110° C. The material was raisedto a temperature of 550° C. at a rate of 5° C./min and held attemperature for 3 hr to calcine the material, which produced a sodiumsilica-alumina gel with a nominal SiO₂/Al₂O₃ ratio of 50. Aftercalcination, all of the sodium silica-alumina gel (26.36 g) was mixedwith 5.92 g of NiCl₂. 6 H₂O dissolved in about 200 mL of deionizedwater. The solution was vigorously stirred, heated to reflux, and leftovernight. After cooling, solids were filtered and washed five times,each time with about 150 mL of hot deionized water. Solids were driedovernight in a vacuum filter with 110° C. air passing though the solids.

Example 2 Preparation of First Oligomerization Catalyst

20.00 g of a beta zeolite powder (e.g., Catalog #CP814-C, ZeolystInternational, Malvern, Pa., USA) was mixed with about 200 mL of asolution containing 4.28 g of anhydrous NiCl₂ dissolved in deionizedwater. The mixture was stirred vigorously and heated to refluxovernight. After cooling, supernatant was decanted from the settledsolids. Solids were transferred to a Millipore® filter with a 0.6 μmdisc, slurried, and filtered several times with about 200 mL of hotdeionized water, and dried overnight at 60° C. After drying, thematerial was heated from room temperature to 550° C. in flowing air andheld for 2 hr at 550° C. to calcine and pelletize the material. Pelletswere then returned to ambient temperature at a rate of 10° C./min.Pellets were ground and then sieved through a −35/+80 mesh filter andcollected.

Example 3 Preparation of First Oligomerization Catalyst

20.00 g of a Si—Al powder (e.g., Davicat SIAL 3111 powder, W. R. Grace &Co., Columbia, Md., USA) was mixed with about 200 mL of a solutioncontaining 13.22 g of anhydrous NiCl₂ dissolved in deionized water. Themixture was stirred vigorously and heated to reflux overnight in aflask. Upon cooling, contents of the flask were washed into a Millipore®filter with a 0.6 μm disc with deionized water, slurried, and filtered12 times with about 150 mL of hot deionized water, and then driedovernight at 60° C. After drying, material was pelletized, ground, andsieved through a −35/+100 mesh filter and collected.

Example 4 Preparation of First Oligomerization Catalyst

The preparation of EXAMPLE 3 was repeated using W. R. Grace & Co.Davicat SIAL 3113 powder.

Example 5 Preparation of First Oligomerization Catalyst

The preparation of EXAMPLE 3 was repeated using W. R. Grace & Co.Davicat SIAL 3125 powder.

Example 6 Preparation of First Oligomerization Catalyst

A Ni-exchanged silica/alumina catalyst using W. R. Grace & Co. DavicatX501 catalyst support was prepared via a column exchange method usingNiCl₂ as the precursor. Davicat X501 extrudate was ground and sieved to30-60 mesh size then calcined in air at 550° C. for about 6 hours. 20 gof this material was placed in a 250 mL chromatography column and rinsedwith DI water to create a well-packed column. Excess DI water wasdrained off and a solution made with 13.22 g of Aldrich 98% NiCl₂ andabout 200 mL of DI water was poured into the reservoir of thechromatography column. Outlet flow rate was adjusted to about 0.25mL/min. The exchange was continued until all of the Ni solution drained.The Ni-exchanged X501 was slurried out of the column with DI water to aMillipore filter assembly equipped with an 0.45 μm nylon filter disk.After the initial supernatant removal, two washes with about 200 mL ofroom temperature DI water and two additional washes with about 250 mL ofhot DI water were conducted. The dissolved solids meter reading afterthe second hot water wash was 14 ppm. The Ni-exchanged X501 material wasdried in a vacuum oven overnight at 60° C. The dried Ni-X501 materialweighed 21.07 g and the Ni loading was determined by ICP to be 0.8 wt %.

Example 7 Preparation of First Oligomerization Catalyst

A Ni-exchanged silica/alumina catalyst using W. R. Grace & Co. DavicatX501 catalyst support is prepared via a column exchange method usingNiCl₂ as the precursor. Davicat X501 extrudate (14.79 g) was pre-treatedwith a 28% ammonia solution overnight at room temperature, then D.I.water washed, and dried overnight at 105° C. The treated and driedsupport was then Ni-ion exchanged with 200 mL of a 6.2 wt % NiCl₂solution via the column exchange method. The catalyst was washed withde-ionized water while on the column until washes contained 8 ppmsolids, then dried in a 60° C. vacuum oven for two days. The catalystwas found to contain 1.26 wt % Ni by ICP analysis.

Example 8 Preparation of a Metathesis Catalyst

39.21 g of dried alumina spheres (e.g., Sasol 2.5/210, Hamburg, Germany)were impregnated with an aqueous solution of ammonium heptamolybdate(54.34% Mo) to produce a final loading of Mo in the alumina spheres ofabout 8 wt %. The impregnated spheres were dried at 120° C. and thencalcined at 680° C. for 2 hrs.

Example 9 First Oligomerization, Test 1

EXAMPLE 9 demonstrates an exemplary first oligomerization process. Thecatalyst of EXAMPLE 3 was used. 1.42 g of the catalyst was loaded into a⅜-inch (1.0 cm) O.D. stainless steel tube supported on a bed of quartzwool for flow reactor testing. A thermocouple was placed at the radialcenter near the bottom of the catalyst bed. Soda lime beads werepositioned above the catalyst bed to preheat the feed gas. The catalystwas pretreated at 300° C. and 0 psig in N₂ flowing at 100 cm³/min atroom temperature and pressure (RTP) for 4 hr. The catalyst was thencooled to 85° C. and the pressure was set to 300 psig. A mixture ofethylene flowing at a rate of 36.7 cm³/min (RTP) and N₂ flowing at arate of 7.5 cm³/min (RTP) was introduced to the reactor via separateexternally calibrated mass flow controllers. The gas mixture was passedthrough a molecular sieve sorbent to remove water and a copper (Cu)sorbent to remove oxygen prior to entering the catalytic reactor.Introduction of the ethylene/N₂ mixture to the reactor was designated astime zero [i.e., Time-On-Stream (TOS)=0 hr]. At a TOS of 116 hr,ethylene conversion was determined to be 97%. Ethylene conversion wassteady at 97% after 312 hr TOS. Reaction product was collected at systempressure in one of two parallel stainless steel vessels chilled to 10°C. to 12.5° C. Concentration of gases in the reactor effluent includingethylene, butenes and N₂ were determined using a Carle packed-column gaschromatograph equipped with an externally calibrated thermalconductivity detector. The gaseous reactor effluent was measured with adigital flow meter (e.g., Agilent, Santa Clara, Calif., USA). Moles ofethylene in the reactor effluent were determined via effluent flow rateand concentration of ethylene assuming an ideal gas effluent. Molarethylene conversion was determined using Equation [1]:

$\begin{matrix}{{Conversion} = {100*\frac{{{Ethylene}({in})} - {{Ethylene}({out})}}{{Ethylene}({in})}}} & \lbrack 1\rbrack\end{matrix}$

Neat liquid products were analyzed with a gas chromatograph (e.g.,Agilent, Santa Clara, Calif., USA) equipped with a mass-selectivedetector. Compounds in the liquid samples were categorized by carbonnumber (e.g. butenes, hexenes, etc.). Peak area corresponding tocompounds categorized together were summed and divided by the total peakarea of the chromatogram to determine relative concentration of eachorganic category as a function of carbon number. Liquid samplescollected between a TOS of 116 hr and 312 hr consisted of 72% C4, 24%C6, 4% C8, and <1% C10+.

Example 10 First Oligomerization, Test 2

1.40 g of the catalyst prepared in EXAMPLE 4 was loaded into the ⅜″ (1.0cm) tube reactor. The process conditions of EXAMPLE 9 were used.Ethylene conversion was 99% through a TOS of 206 hr (FIG. 7). Liquidsamples collected between 129 TOS and 206 hr TOS consisted of 72% C4,21% C6, 6% C8, and 2% C10+.

Example 11 First Oligomerization, Test 3

1.45 g of the catalyst prepared in EXAMPLE 5 was loaded into the ⅜″ tubereactor. Process conditions of EXAMPLE 9 were used. Ethylene conversionincreased from 66% to 95% over a TOS of 32 hr to 83 hr. Ethyleneconversion then remained steady at 95% to 98% up to a TOS of 201 hr. Asshown in FIG. 8, liquid samples had a steady composition ofapproximately 73% C4, 24% C6, 3% C8, and <1% C10+.

Example 12 First Oligomerization, Test 4

1.40 g of the catalyst prepared in EXAMPLE 3 was loaded into a ⅜″ (1.0cm) tube reactor. Process conditions of EXAMPLE 9 were used. At 1153 hrTOS, ethylene conversion was 51%. Liquid samples collected at 1153 hrTOS consisted of 66% C4, 30% C6, and 3% C8. At 1154 hr TOS, the catalystwas regenerated by lowering the reactor pressure to 0 psig, raising thetemperature of the catalyst bed to 300° C. and passing 100 cm³/min of N₂over the catalyst for 4 hr. After reactivation, reactor temperature waslowered to 85° C., pressurized to 300 psig, and the reaction mixture wasreintroduced to the reactor. After reactivation, ethylene conversion wasmeasured to be 93-98% between 1183-1256 hr TOS. Liquid samples collectedbetween 1183-1256 hr TOS averaged 68% C4, 29% C6, and 4% C8. From 1256hr TOS to termination of the run at 2247 hr TOS, two more regenerationswere conducted. Ethylene conversion after final regeneration was 44-45%.Liquid samples collected between 1256 TOS and 2247 hr TOS were similarin relative organic compound concentration of 67% C4, 29% C6, 3% C8, and1% C10+. A total of about 2.9 L oligomerized product was collected overthe 2247 hr run.

Example 13 Second Oligomerization, Test 1

EXAMPLE 13 demonstrates conversion of a first oligomerization product tofuel-range hydrocarbons in a second oligomerization reactor. 1.64 g ofW. R. Grace & Co. Davicat 3111 (−35/+100) mesh which had been calcinedat 400° C. for 2 hrs in air was loaded in a ⅜″ (1.0 cm) O.D. stainlesssteel tube reactor for reaction testing. Liquid produced during aportion of the test described in EXAMPLE 12 was fed to the top of thereactor at 0.1 mL/min. N₂ was fed to the top of the reactor as a carriergas at a flow rate of 10 cm³/min. The pressure of the reactor wasmaintained at a nominal value of 300 psig. Reactor temperature wasmonitored via a thermocouple placed at the radial center near the bottomof the catalyst bed. Temperature was maintained at 225° C. Liquid feedand reactor products were analyzed neat with a gas chromatograph (e.g.,Agilent, Santa Clara, Calif., USA) equipped with a mass-selectivedetector. Compounds in the liquid samples were categorized by carbonnumber (e.g. butenes, hexenes, etc.). Peak area of compounds categorizedtogether were summed and divided by the total peak area of thechromatogram to determine the relative concentration of each organiccategory as a function of carbon number. FIG. 9a shows typical GC/MSdata for the first oligomerization product used as feed to the top ofthe second oligomerization reactor, and the second oligomerizationproduct collected from the bottom of the reactor (FIG. 9b ). Resultsdemonstrate conversion of light olefins in the feed to heavier olefinsin the product. In FIG. 10, the carbon number distribution of feed andproduct samples taken over the course of 117 hours TOS demonstratesstable production of fuel-range hydrocarbons.

Example 14 Second Oligomerization, Test 2

EXAMPLE 14 demonstrates the effect of temperature on the conversion offirst oligomerization products to fuel-range hydrocarbons in a secondoligomerization reactor. Testing and analysis was conducted as describedin EXAMPLE 13. H-Beta zeolite (e.g., −30/+100 mesh zeolite, GuildAssociates, Dublin, Ohio, USA) was calcined ex-situ in air at atemperature of 550° C. for 3 hr. 0.50 g of the calcined zeolite wasloaded into the tube reactor. Feed was introduced to the reactor at arate of 0.05 mL/min. A carrier gas of nitrogen (N₂) was fed to thereactor at a flow rate of 7.4 cm³/min. The reactor was maintained at anominal pressure of 300 psig. Temperature of the reactor wasperiodically increased. Liquid product was collected at system pressurein condensers chilled to a temperature of 10° C. TABLE 1 reports thereactor bed temperature and concentration of organic species as afunction of carbon number for liquid samples at each reactiontemperature.

TABLE 1 compares second oligomerization reactor bed temperature andconcentration of organic species as a function of carbon number fortests with H-Beta zeolite catalyst.

Composition by Carbon Reactor Temperature, ° C. No. 200 225 250 275 300325 350 C4  9%  8%  7%  6%  7%  7%  8% C5  1%  2%  2%  3%  3%  3%  2% C619% 17% 17% 16% 19% 18% 25% C7  1%  2%  2%  3%  3%  4%  2% C8 20% 20%20% 21% 23% 23% 26% C9  2%  2%  3%  3%  2%  3%  1% C10 20% 19% 20% 20%20% 19% 19% C11  1%  1%  1%  1%  1%  1%  0% C12 12% 12% 12% 12% 11% 10% 8% C13  1%  2%  2%  2%  2%  2%  1% C14  8%  8%  8%  8%  6%  6%  4% C16 5%  2%  5%  5%  3%  3%  2% C18  2%  8%  1%  1% Yield C8+ 69% 70% 70%71% 67% 66% 61% Yield C10+ 48% 48% 48% 48% 42% 41% 35%

FIG. 11 shows simulated distillation profiles for products generated ateach reactor temperature, along with reference standards for keroseneand diesel fuel. Simulated yields of C8+ and C10+ compounds are reportedassuming 98% conversion of ethylene from the ethylene oligomerizationdescribed in Example 12. FIG. 12 compares product composition at 250° C.with those obtained with other catalysts at the same temperature.

Example 15 Second Oligomerization, Test 3

0.50 g of CBV 3104 catalyst of a (−80/+100) mesh (Zeolyst International,Malvern, Pa., USA) was calcined at 550° C. for 4 hrs in air and loadedand tested with an identical feed and in a similar manner as describedin Example 14. TABLE 2 lists compositions of liquid product samplesobtained at various reactor temperatures.

TABLE 2 compares compositions of liquid product samples obtained atvarious reactor temperatures for second oligomerization tests with CBV3104 catalyst.

Composition by Reactor Temperature, ° C. Carbon No. 200 250 300 350 C45% 3% 2% 4% C5 1% 2% 5% 6% C6 15%  12%  9% 10%  C7 1% 3% 8% 9% C8 17% 14%  13%  13%  C9 1% 4% 8% 8% C10 22%  21%  18%  19%  C11 1% 1% 3% 3%C12 16%  14%  14%  12%  C13 2% 3% 3% 3% C14 10%  10%  10%  8% C16 7% 7%6% 4% C18 2% 3% 2% 1% C20+ 1% 1% Yield C8+ 77%  77%  74%  69%  YieldC10+ 59%  60%  54%  48% 

FIG. 12 compares the product composition at 250° C. with those obtainedwith other catalysts at the same temperature.

Example 16 Second Oligomerization, Test 4

0.50 g of W. R. Grace & Co. Davicat 3111 (−35/+100) mesh which had beencalcined at 400° C. for 2 hrs in air was loaded and tested in mannersimilar to the method disclosed in EXAMPLE 14. Liquid produced during aportion of the test described in EXAMPLE 12 was fed to the reactor at0.05 mL/min. TABLE 3 lists compositions of samples taken from the liquidproduct at various reactor temperatures.

TABLE 3 lists compositions of samples taken from the liquid productobtained at various second oligomerization reactor temperatures usingGrace 3111 as catalyst.

Reactor Temperature, ° C. Composition 200 250 300 350 C4 7% 12%  6% 7%C5 2% 2% 3% 3% C6 14%  23%  18%  23%  C7 2% 2% 3% 3% C8 17%  20%  22% 26%  C9 3% 2% 3% 2% C10 19%  17%  19%  18%  C11 1% 1% 1% 1% C12 13% 10%  11%  9% C13 1% 1% 2% 1% C14 10%  6% 7% 4% C16 7% 3% 4% 2% C18 3% 1%1% C20+ Yield C8+ 73     60     68     63     Yield C10+ 53     38    44     35    

FIG. 12 compares product composition at 250° C. with those obtained withother catalysts at the same temperature.

Example 17 50:50 Recycle of First and Second Oligomerization Products

EXAMPLE 17 demonstrates recycling of second oligomerization lightproducts back through the second oligomerization reactor and process toincrease molecular weight to form fuel-range hydrocarbons. One part byweight of a second oligomerization distillate fraction containing lighthydrocarbons boiling at a temperature less than 136.8° C. (obtained bydistillation of a second oligomerization product) was mixed with onepart by weight of a composite sample taken from a typical firstoligomerization product to produce a 50:50 mixture that was used as afeed to the second oligomerization reactor. Testing and product analyseswere performed as described in EXAMPLE 13. 1.63 g of W. R. Grace & Co.Davicat SiAl 3111 (−60/+100 mesh) was loaded into the flow reactor forthe recycle testing. Reactor bed temperature was held at 225° C. and apressure of 300 psig. Product obtained at a feed rate of 0.10 mL/mincontained compounds with carbon numbers ≥C8 of 68% and ≥C10 of 45%comparable to the product obtained in EXAMPLE 15 (100% firstoligomerization product feed, i.e., no recycle). FIG. 13 comparesproduct composition for 50% recycle at 225° C. with products fromcomparable experiments performed at the same temperature with no recyclestage (i.e., single pass first oligomerization product as a feed) andwith a feed consisting of 100% recycled second oligomerization lightsdescribed in EXAMPLE 18. Product compositions are similar for theserecycle experiments.

The 50% recycle experiment was continued by first regenerating thecatalyst at 550° C. for 4 h in air, after which the liquid feed rate wasdecreased to 0.075 mL/min to determine the effect of feed rate. Resultsshow that decreasing the feed rate shifted the composition toward ahigher carbon number. At a flow rate of 0.075 mL/min, composition showedcompounds were obtained with a carbon numbers ≥C8 of 79% and ≥C10 of57%.

Example 18 Recycle of Light Olefins from Second Oligomerization Back toSecond Oligomerization Stage or Process

A feed consisting of 100% distilled lights from second oligomerizationproducts boiling at a temperature less than 150° C. were passed over acatalyst bed comprised of 1.57 g of Grace Davicat SIAL 3111 at a flowrate of 0.066 mL/min, at a temperature of 225° C. and a reactor pressureof 300 psig. Product obtained contained compounds with a carbon number≥C8 of 80% and ≥C10 of 44%. FIG. 13 compares product composition at 225°C. with comparable experiments performed at the same temperature andvarying degrees of recycle. Light olefin products from the secondoligomerization stage or process can be recycled without dilution backto the second oligomerization reactor for conversion to fuel-rangeproducts, increasing the overall yield after a single recycle to ≥C8 ofabout 90% and ≥C10 of about 70%.

Example 19 Integration of Ethanol Dehydration with First OligomerizationStage or Process

EXAMPLE 19 demonstrates the integration of an ethanol dehydrationprocess with the first oligomerization stage or process. Ethanol (96 wt% in water) was fed to a ⅜″ OD stainless steel tube reactor loaded with1.10 g of W. R. Grace & Co. Davicat SIAL 3111 catalyst. Catalyst wascalcined at 500° C. for 4 hrs and sized to −60/+100 mesh prior toloading. Ethanol was fed to the reactor at a rate of 0.1 mL/min at 360°C. and a pressure of 300 psig. N₂ was used as a carrier gas that wasco-fed to the reactor at a rate of 12.4 cm³/min. Ethanol conversion wasbetween 90% and 95%. Ethylene yield was 55% to 67% on average. Gaseouseffluent from the reactor was passed through silica gel and activatedcarbon filters prior to entering the molecular sieve and Cu scrubbers.Ethylene-rich reactor effluent then passed over the catalyst disclosedin EXAMPLE 3 at 85° C. and 300 psig. Other parameters for this reactorwere similar to the process disclosed in EXAMPLE 9. Ethylene conversionof 98-100% was observed. The liquid product consisted of 65% C4, 21% C6,9% C8, 5% C10 and 1% C12.

Example 20 Olefin Metathesis

EXAMPLE 20 demonstrates results from exemplary olefin metathesis of acomposite mixture containing a 50:50 mixture of a first oligomerizationtest product and a second oligomerization test product that were reactedwith ethylene. 1.7 g of the catalyst prepared in EXAMPLE 8 was loadedinto a ⅜″ stainless steel tube reactor. Reactor temperature was 120° C.Reactor pressure was held at 300 psig. The liquid feed was introduced tothe reactor at a rate of 0.044 mL/min. Ethylene was fed to the reactorat a rate of 29 cm³/min. TABLE 4 discloses the relative concentration ofthe liquid reactor products as grouped by carbon number. The gas phaseproduct contained 6% propene.

TABLE 4 lists relative concentrations of liquid reactor products fromolefin metathesis testing grouped by carbon number.

Composition Liquid Feed Liquid Product C4 58 59 C5 14 C6 26 19 C7 2 C811 4 C9 C10 5 1 C11 C12 1 C13 C14 C16 C18

Example 21 One Step Process

25.28 g of Zeolyst CBV3020 CY 1.6 (Si/Al₂ ratio: 30) catalyst was loadedinto a 60 cm³ stainless steel tube for reaction testing. The reactor wasoperated over several days at a temperature between 270° C. and 350° C.and a pressure between 150 psig and 500 psig. Ethanol flow to thereactor was varied from 0.20 to 1.00 mL/min. Ethanol concentrationvaried from 85% ethanol in water to 100% ethanol. A N₂ carrier gas alsopassed through the reactor at 25-50 cm³/min. About 2 L of material wereproduced during several days of testing. At 340° C. using 85% ethanol inwater and a liquid feed flow rate of 1.00 mL/min, the hydrocarbon yieldwas 63.29% on a gram liquid hydrocarbon produced per gram of ethylenefed basis. (Ethanol was fed to the reactor but yield was calculated onthe ethylene weight basis.) At 350° C., 350 psig and 0.2 mL/min, thehydrocarbon yield was 44.9-46.3% over 3 days. The liquid samplesproduced were composited into a single sample with a carbon numbercomposition of ≥C8 of 85.2% and ≥C10 of 61.9%. The aromatic content ofthis composite can be estimated to be 75% to 85% as indicated by thecycloparaffin content of the hydrotreated product, discussed in EXAMPLE30.

Example 22 One Step Process, Test 2

EXAMPLE 21 was repeated except that 31.1 g of Zeolyst CBV 28014 CY 1.6(Si/Al₂=280) catalyst was used. The reactor was operated over a periodof several days. Temperature was selected between 340° C. and 360° C.Reactor pressure was 150 psig. Ethanol flow to the reactor was variedfrom 0.10 to 0.30 mL/min. Ethanol concentration was 92.5% ethanol inwater. A N₂ carrier gas also passed through the reactor at 50 cm³/min.Liquid products were composited to a single sample with a carbon numbercomposition of ≥C8 of 77.5% and ≥C10 of 48.1%.

Example 23 Alkylation

EXAMPLE 23 demonstrates alkylation of one-step light products withethylene to increase yield of fuel-range hydrocarbons. A portion of thecomposited hydrocarbon produced in EXAMPLE 22 was fractionated bydistillation up to a temperature of 115° C. to collect a quantity oflight hydrocarbons. 8.3 g of the light hydrocarbons were added to 0.45 gH-ZSM-5 catalyst (Zeolyst CBV 28014 powder calcined 500° C., 4 hr inair) in a steel autoclave vessel. The vessel was sealed and ethylene wascharged to 100 psig at room temperature. The mixture was heated (whilestirring) to 250° C. internal temperature and continued overnight. Massof the hydrocarbon mixture increased by 0.81 g. FIG. 14 shows simulateddistillation curves of the feed (light distillate fraction) andalkylated product (alkylation of lights). The feed had a compositionwith a carbon number distribution of ≥C8 of 55.5% and ≥C10 of 10.4%. Thealkylated product had a greater fraction in the distillate fuel rangewith a composition with a carbon number distribution of ≥C8 of 60.3% and≥C10 of 15.4%.

Example 24 Alkylation

A product produced by the method of EXAMPLE 21 was fractionated untilthe vapor temperature of the distilling lights increased to 125° C. Thefraction that distilled up to 125° C. was alkylated with ethylene. 2.83g of BASF Beta 35 zeolite (L7134-47-2) was added to 80.65 g of thedistilled fraction in a stainless steel autoclave vessel. The autoclavewas sealed and heated to 250° C. Ethylene was added such that the totalpressure was 2400 psig at temperature. After 14 hrs, the pressure haddecreased to 2000 psig. The feed had a composition with a carbon numberdistribution of ≥C8 of 48.5% and ≥C10 of 11.0%. The alkylated producthad a greater fraction in the distillate fuel range with a compositionwith a carbon number distribution of ≥C8 of 71.3% and ≥C10 of 43.0%.

Example 25 Alkylation of a Mixture Containing a One-Step Product and aTwo-Step Oligomerization Product

EXAMPLE 25 demonstrates alkylation of a one-step product with a two-stepfirst oligomerization product. 53.0 g of the fraction of a one-stepproduct prepared by the method of EXAMPLE 21 distilling between 115 and135° C. was mixed with 43.0 g of first oligomerization product producedby the method of EXAMPLE 9, except using the catalyst of EXAMPLE 1. Thehydrocarbon mixture was fed at 0.1 mL/min (WHSV=4) with 6 mL/min of N₂carrier gas over a Beta zeolite catalyst (Zeolyst CP814C; Si/Alratio=38) at 250° C. Reactor pressure was 500 psig. Results show thealkylation increased the carbon number in the product. Composition ofthe feed included a carbon number distribution of ≥C8 of 74% and ≥C10 of4%. Composition of the product included a carbon number distribution of≥C8 of 89% and ≥C10 of 33%.

Example 26 Hydrotreatment of a One-Step Product

EXAMPLE 21 was repeated except that 1.00 g of Zeolyst CBV3024 CY 1.6(Si/Al₂=80) catalyst was used in a ⅜″ OD stainless steel reactor. Overthe course of several days, the reactor was operated at 360° C. and 230psig. Ethanol flow to the reactor was varied from 0.08-0.15 mL/min.Ethanol concentration was 53% ethanol in water. A N₂ carrier gas wasalso passed through the reactor at 25 cm³/min. The combined product wasfractionated to collect the material distilling above 140° C. A portionof this material (173.61 g) was placed in a steel autoclave and 12.12 gof 2% Pt on ⅛″ Al₂O₃ pellets from Engelhard was added. The autoclave wassealed, pressurized with H₂ and heated to 200° C. for one day. Thepressure was maintained at 400 psig by periodic additions of H₂. FIG. 15shows the NMR spectrum of the product. Results demonstrate that use ofthese conditions for light hydrotreating of one-step products does notreduce aromatic groups to cyclic paraffins under the selected reactionconditions over the Pt catalyst. By integration of the NMR spectrum,23.5% of the carbon in this lightly hydrotreated material is in anaromatic ring.

Example 27 Hydrotreatment of a Two-Step Product

EXAMPLE 27 demonstrates light hydrotreating of two-step products todistillate fuel-range hydrocarbons under selected conditions, in whicharomatics were shown not to be reduced. In a steel autoclave, 12.12 g of2% Pt on ⅛″ Al₂O₃ pellets from Engelhard was added to 327 g of thefraction of the second oligomerization product from EXAMPLE 16 producedat 225° C. that distills above 150° C. FIG. 16 shows the NMR spectrum ofthe olefin feed. The spectrum shows the presence of highly branchedolefins at a level consistent with about one olefin group per molecule.The autoclave was sealed, pressurized with H₂ and heated to 200° C.Pressure was maintained at 425 psig by periodic additions of H₂. Thehydrogenation reaction continued overnight. FIG. 17 presents NMRanalysis results for the hydrotreated product hydrotreated underconditions that do not reduce aromatics. Results show that no aromaticor olefinic carbons are present in the product and that thehydrotreating conditions are sufficient to reduce the olefins toiso-paraffins. FIG. 18 presents simulated distillation (simdist)results. Data show that most of the hydrotreated product is in the jetfuel range. Data in the figure also show that simdist results of olefinfeeds are identical to those for the hydrotreated materials.

Example 28 Fractionation and Hydrotreatment of a Two-Step Product to aJet Fuel

EXAMPLE 28 demonstrates hydrotreating of two-step products to distillatefuel-range hydrocarbons under selective conditions of EXAMPLE 26, inwhich aromatics were shown not to be reduced. In a steel autoclave,12.12 g of 2% Pt on ⅛″ Al₂O₃ pellets from Engelhard was reused fromEXAMPLE 26 to reduce composites of the fraction of the secondoligomerization product prepared by the method of EXAMPLE 16 produced at225° C. that distills above about 140° C. Several batches were reducedin order to collect about 1.5 L of lightly hydrotreated product. Theautoclave was sealed, pressurized with H₂ to between 400 and 500 psigand heated to 200° C. Each hydrogenation reaction continued overnight.Hydrotreated materials were composited and fractionally distilled. Thefraction distilling from about 150 to about 270° C. comprising about 1 Lwas submitted to the Air Force Research Laboratory (AFRL) for testingunder guidelines of ASTM D4054, “Standard Practice for the qualificationand Approval of new Aviation Turbine Fuels and Fuels Additives.” Thetesting was to determine the suitability of the material as analternative aviation fuel that could satisfy the specificationrequirements outlined in D7566-12A. TABLE 5 lists results of GC×GCtesting.

TABLE 5 lists results from GC×GC testing of two-step product fromEXAMPLE 28 conducted by AFRL.

Component Weight % Volume % Total Alkylbenzenes 0.98 0.78 TotalAlkylnaphthalenes <0.01 <0.01 Total Cycloaromatics 0.60 0.49 Totaliso-Paraffins 96.84 97.19 Total n-Paraffins 0.79 0.82 TotalMonocycloparaffins 0.75 0.70 Total Dicycloparaffins 0.03 0.03 TotalTricycloparaffins <0.01 <0.01

Results confirm the low aromatic content and the very high isoparaffincompound content. TABLE 6 compares product properties for a test sampleagainst ASTM specifications for two aviation jet fuels.

TABLE 6 compares product properties for a hydrotreated and fractionatedtwo-step product against ASTM specifications for two aviation jet fuels.

Method Test D7566 Jet A-1 Result ASTM D 86 Distillation: Initial BoilingPoint 164 (° C.) 10% Recovered (° C.) <205 <205 177 20% Recovered (° C.)182 50% Recovered (° C.) 205 90% Recovered (° C.) 254 Endpoint (° C.)<300 <300 272 Residue (% vol) <1.5 1.6 Loss (% vol) <1.5 0.7T90-T10 >22 >40 77 T50-T10 >15 28 ASTM D 93 Flash Point (° C.) 38 38 52ASTM D 3241 Thermal Stability 325 260 JFTOT @325 (° C.) Tube DepositRating <3 <3 1 (Visual) Change in Pressure <25 <25 0 (mm Hg) ASTM D 4809Net Heat of >42.8 43.7 Combustion (MJ/kg) ASTM D 7171 Hydrogen Content15.2 by NMR (% mass) ASTM D 5972 Freeze Point (° C.) <−40 <−47 <−70 ASTMD 4052 Density (kg/L, 15° C.) 0.730 to 0.775 to 0.775 0.770 0.840

Example 29 Preparation of a Two-Step Product, Hydrotreatment, andFractionation to Diesel and Gasoline Fuels

EXAMPLE 29 demonstrates the conversion of first oligomerization productsto fuel-range hydrocarbons in a second oligomerization reactor,hydrotreatment and fractionation to a diesel range alternate fuel.H-Beta zeolite (e.g., −12 to +30 mesh zeolite, Guild Associates, Dublin,Ohio, USA) was calcined ex-situ in air at a temperature of 550° C. for 3hr. 13.9 g of the calcined zeolite was loaded into a tube reactor. Firstoligomerization product was introduced to the reactor at a rate of1.4033 mL/min. A carrier gas of nitrogen (N₂) was fed to the reactor ata flow rate of about 10 cm³/min. The reactor was maintained at a nominalpressure of 300 psig and a temperature of 225° C. Liquid product wascollected at system pressure in condensers chilled to a temperature of10° C. Second oligomerization product was lightly hydrotreated using themethod of EXAMPLE 27. The hydrotreated material was distilled and thefraction boiling between about 160 and about 390° C. was collected.Simulated distillation of this fraction shown in FIG. 19 demonstratesthe material had distillation properties nearly identical to a standarddiesel fuel. The material had a pour point of −66.0° C., a cloud pointof −60.1° C., and a derived cetane value of 53.6. The light fractionboiling below 160° C. was a gasoline fraction with an octane number of83.

Example 30 Fractionation and Hydrotreatment of a One-Step Product to aFuel Blend

A portion of the composite of one-step hydrocarbon products obtained inEXAMPLE 21 was hydrotreated over 406 g of a Engelhard Ni 0750 catalyst(Iselin, N.J.) in a fixed bed reactor. Hydrogenation was conducted undermild, medium, and heavy treatment conditions as described in TABLE 7.The key properties of density and freeze point for each set ofconditions are shown demonstrating that at least a medium treatment iseffective at attaining freeze points lower than the target −47° C. Acomposite of the hydrogenated product was fractionated and the fractionboiling between about 150° C. and about 200° C. was collected anddesignated H2-1. A second portion of the hydrogenated product was alsofractionated and the fraction boiling between about 150° C. and about230° C. was collected and designated H2-2. Samples were submitted to theAir Force Research Laboratory (AFRL) for testing under guidelines ofASTM D4054, “Standard Practice for the qualification and Approval of newAviation Turbine Fuels and Fuels Additives.” Testing determinedsuitability of the material as an alternative aviation fuel that couldsatisfy the specification requirements outlined in D7566-12A. TABLE 8lists results of GC×GC testing.

TABLE 7 lists nominal processing conditions and properties ofhydrotreated one-step products.

Temperature, Pressure, LHSV, Freeze Density, Sample ° C. psig h⁻¹ Point,° C. kg/L Feed — — — −14.3 Heavy 200 1000 0.5 −73 0.788 Treatment Medium180 700 0.5 −52 0.793 Treatment Mild 160 450 0.625 −37 0.799 Treatment

TABLE 8 lists results from GC×GC testing of one-step products fromEXAMPLE 30 conducted by AFRL.

7933 7934 4909 4751 GCxGC (mass %) H2-1 H2-2 F-T SPK JP-8 n-Paraffins0.3 0.2 19.1 18.8 iso-Paraffins 5.7 5.8 79.5 31.4 Monocycloparaffins85.5 74.5 1.2 20.8 Dicycloparaffins 6.0 16.2 <0.1 5.7 Alkylbenzenes 2.42.9 0.2 15.1 Indans and Tetralins 0.1 0.4 0.1 6.5 Naphthalene <0.1 <0.1<0.1 0.1 Naphthalenes <0.1 <0.1 <0.1 1.6 Total 100 100 100 100

Results confirm the high cyclic paraffin content, which arises fromhydrotreatment of the highly aromatic one-step reactor product. TABLE 9compares product properties for a test sample against ASTMspecifications for two aviation jet fuels.

TABLE 9 compares product properties for hydrotreated and fractionatedone-step products against ASTM specifications for two aviation jetfuels.

MIL-DTL- 83133H Spec Require- 7933 7934 4909 4751 Specification Testment H2-1* H2-2* FT-SPK* JP-8* Aromatics, vol % ≤25 1.9 2.2 0.0 18.8Olefins, vol % 1.2 1.1 0.0 0.8 Heat of Combustion ≥42.8 43.1 43.1 44.343.3 (measured), MJ/Kg Distillation: IBP, ° C. 161 165 144 159 10%recovered, ° C. ≤205 165 171 167 182 20% recovered, ° C. 166 173 177 18950% recovered, ° C. 171 183 206 208 90% recovered, ° C. 190 220 256 244EP, ° C. ≤300 214 243 275 265 T90-T10, ° C. 22 25 49 89 62 Residue, %vol ≤1.5 1.1 1.1 1.5 1.3 Loss, % vol ≤1.5 1 0.8 0.9 0.8 Flash point, °C. ≥38 44 48 45 51 Freeze Point, ° C. ≤−47 <−60 <−60 −51 −50 Density@15°C., 0.775- 0.803 0.814 0.756 0.804 kg/L 0.840 (0.751- 0.770)

FIG. 20 presents simulated distillation (simdist) results for the H2-1and H2-2 products. Data show that the H2-1 product has a distillationprofile nearly identical to a standard kerosene. H2-2 is heavier andclosely resembles a jet fuel or jet blend stock.

While exemplary embodiments of the present invention have been shown anddescribed, it will be apparent to those skilled in the art that manychanges and modifications may be made without departing from theinvention in its true scope and broader aspects. The appended claims aretherefore intended to cover all such changes and modifications as fallwithin the scope of the present invention.

What is claimed is:
 1. A process for providing a fuel blend, comprising:(i) combining together a first hydrocarbon product, a second hydrocarbonproduct, and a two-step oligomerization product to obtain the fuelblend; or (ii) combining together the first hydrocarbon product and thetwo-step oligomerization product to obtain the fuel blend; wherein: thefirst hydrocarbon product is derived from an ethanol-containing feed,the first hydrocarbon product containing hydrocarbons with a carbonnumber from about C2 to about C12 and comprising a majorityconcentration of mixed cycloparaffin hydrocarbons and mixed closed chainaromatic hydrocarbons; the second hydrocarbon product comprisesalkylated aromatic hydrocarbons; and the two-step oligomerizationproduct comprises mixed linear and branched olefins with a carbon numberfrom about C8 to about C23 in a yield of greater than or equal to 20%and wherein the two-step oligomerization product is derived from anethylene-containing feed via a two-step oligomerization process, whichcomprises (i) passing the ethylene-containing feed over a catalystcomprising a metal deposited on a support at a temperature ranging fromabout 40° C. to 220° C. to form a first oligomerization product and (ii)passing the first oligomerization product over a solid acid catalyst ata temperature ranging from greater than 150° C. to about 450° C. to formthe two-step oligomerization product.
 2. The process of claim 1, whereinthe two-step oligomerization process further comprises passing theethylene-containing feed to a gas purification zone to remove water; andwherein the first oligomerization product comprises a majorityconcentration of mixed olefins with a carbon number from about C4 toabout C8.
 3. The process of claim 1, further including mixing the firstoligomerization product with the first hydrocarbon product to make afeed, and alkylating the feed over an alkylation catalyst to form thesecond hydrocarbon product comprising alkylated aromatic hydrocarbons.4. The process of claim 3, wherein the second hydrocarbon productcontains more hydrocarbons with carbon numbers greater than C8 than thefeed.
 5. The process of claim 3, wherein the second hydrocarbon productcontains more hydrocarbons with carbon numbers greater than C10 than thefeed.
 6. The process of claim 1, further including hydrotreating thefuel blend to yield a majority of fuel range hydrocarbons boiling in therange of temperatures from about 120° C. to about 390° C.
 7. The processof claim 1, further including hydrotreating each of the firsthydrocarbon product, the second hydrocarbon product, and the two-stepoligomerization product or the first hydrocarbon product and thetwo-step oligomerization product prior to combining together (i) thefirst hydrocarbon product, the second hydrocarbon product, and thetwo-step oligomerization product or (ii) the first hydrocarbon productand the two-step oligomerization product to yield a majority of fuelrange hydrocarbons boiling in the range of temperatures from about 120°C. to about 390° C.
 8. The process of claim 1, further includingfractionating the two-step oligomerization product at a selectedfractionation temperature to obtain individual fractions, including afraction containing distillate range olefins boiling at or higher thanthe fractionation temperature and a light fraction boiling at or belowthe fractionation temperature.
 9. The process of claim 8, wherein thefractionation temperature is selected in the range from about 100° C. toabout 140° C.
 10. The process of claim 8, wherein the fractionationtemperature is selected in the range from about 140° C. to about 180° C.11. The process of claim 8, further including hydrogenating thedistillate-range olefins to form a mixture of open-chain hydrocarbonsincluding linear and branched open chain paraffins.
 12. The process ofclaim 11, wherein a majority of open-chain hydrocarbons in the mixtureare in the jet fuel range.
 13. The process of claim 11, wherein amajority of open-chain hydrocarbons in the mixture are in the dieselfuel range.
 14. The process of claim 8, further including mixing thelight fraction with the first hydrocarbon product containing aromatichydrocarbons to make a feed, and alkylating the feed over an alkylationcatalyst to form the second hydrocarbon product comprising alkylatedaromatic hydrocarbons.
 15. The process of claim 14, wherein the secondhydrocarbon product contains more hydrocarbons with carbon numbersgreater than C8 than the feed.
 16. The process of claim 14, wherein thesecond hydrocarbon product contains more hydrocarbons with carbonnumbers greater than C10 than the feed.
 17. The process of claim 1,further including mixing ethylene or an ethylene containing feed with aportion of the first hydrocarbon product containing aromatichydrocarbons to make a feed, and alkylating the feed over an alkylationcatalyst to form the second hydrocarbon product comprising alkylatedaromatic hydrocarbons.
 18. The process of claim 17, wherein the secondhydrocarbon product contains more hydrocarbons with carbon numbersgreater than C8 than the feed.
 19. The process of claim 17, wherein thesecond hydrocarbon product contains more hydrocarbons with carbonnumbers greater than C10 than the feed.
 20. The process of claim 1,wherein the first hydrocarbon product containing aromatic hydrocarbonsand the second hydrocarbon product containing alkylated aromatichydrocarbons are combined to make a feed and hydrogenating the feed toobtain a mixture of closed-chain hydrocarbons including closed-chainaromatics and closed-chain paraffins.
 21. The process of claim 20,wherein hydrogenating includes converting between greater than 0% toabout 33% of the closed-chain aromatics to closed-chain paraffins. 22.The process of claim 20, wherein hydrogenating includes converting fromabout 33% to about 66% of the closed-chain aromatics to closed-chainparaffins.
 23. The process of claim 20, wherein hydrogenating includesconverting from about 66% to about 100% of the closed-chain aromatics toclosed-chain paraffins.
 24. The process of claim 20, comprising (i)fractionating the two-step oligomerization product at a fractionationtemperature to provide a fraction of the two-step oligomerizationproduct containing distillate-range olefins boiling at or higher thanthe fractionation temperature; (ii) hydrogenating the fraction of thetwo-step oligomerization product containing distillate-range olefinsboiling at or higher than the fractionation temperature to provide amixture comprising open chain hydrocarbons; and (iii) combining themixture containing open chain hydrocarbons with the mixture containingclosed-chain hydrocarbons to provide the fuel blend.
 25. The process ofclaim 24, further including fractionating the fuel blend to obtainindividual fractions, including a fraction containing distillate rangehydrocarbons boiling in the range of temperatures from about 120° C. toabout 300° C., a light fraction boiling below a temperature of about120° C., and a heavy fraction boiling above a temperature of about 300°C.
 26. The process of claim 25, wherein the distillate rangehydrocarbons are in the jet fuel range.
 27. The process of claim 25,wherein the light fraction contains hydrocarbons in the gasoline fuelrange.
 28. The process of claim 24, further including fractionating thefuel blend to obtain individual fractions, including a fractioncontaining distillate range hydrocarbons boiling in the range oftemperatures from about 160° C. to about 390° C., a light fractionboiling below a temperature of about 160° C., and a heavy fractionboiling above a temperature of about 390° C.
 29. The process of claim28, wherein the distillate range hydrocarbons are in the diesel fuelrange.
 30. The process of claim 28, wherein the light fraction containshydrocarbons in the gasoline fuel range.
 31. The process of claim 1,comprising (i) fractionating the two-step oligomerization product at afractionation temperature to provide a fraction of the two-stepoligomerization product containing distillate-range olefins boiling ator higher than the fractionation temperature and (ii) combining thefraction of the two-step oligomerization product containingdistillate-range olefins boiling at or higher than the fractionationtemperature with the first hydrocarbon product containing aromatichydrocarbons and the second hydrocarbon product containing alkylatedaromatic hydrocarbons to provide the fuel blend.
 32. The process ofclaim 31, wherein the fuel blend includes up to 33% distillate rangeolefins.
 33. The process of claim 31, wherein the fuel blend includes upto 66% distillate range olefins.
 34. The process of claim 31, whereinthe fuel blend includes up to 100% distillate range olefins.
 35. Theprocess of claim 31, further including hydrogenating the fuel blend toobtain a hydrogenated blend comprising a mixture of closed-chainaromatics, closed-chain paraffins, open-chain paraffins, and open-chainiso paraffins.
 36. The process of claim 35, wherein hydrogenatingincludes converting between greater than 0% to about 33% of theclosed-chain aromatics to closed-chain paraffins.
 37. The process ofclaim 35, wherein hydrogenating includes converting from about 33% toabout 66% of the closed-chain aromatics to closed-chain paraffins. 38.The process of claim 35, wherein hydrogenating includes converting fromabout 66% to about 100% of the closed-chain aromatics to closed-chainparaffins.
 39. The process of claim 35, further including fractionatingthe fuel blend to obtain individual fractions, including a fractioncontaining distillate range hydrocarbons boiling in the range oftemperatures from about 120° C. to about 300° C., a light fractionboiling below a temperature of about 120° C., and a heavy fractionboiling above a temperature of about 300° C.
 40. The process of claim39, wherein the distillate range hydrocarbons are in the jet fuel range.41. The process of claim 39, wherein the light fraction containshydrocarbons in the gasoline fuel range.
 42. The process of claim 35,further including fractionating the hydrogenated blend to obtainindividual fractions, including a fraction containing distillate rangehydrocarbons boiling in the range of temperatures from about 160° C. toabout 390° C., a light fraction boiling below a temperature of about160° C., and a heavy fraction boiling above a temperature of about 390°C.
 43. The process of claim 42, wherein the distillate rangehydrocarbons are in the diesel fuel range.
 44. The process of claim 42,wherein the light fraction contains hydrocarbons in the gasoline fuelrange.
 45. A process for conversion of feedstocks to distillate rangehydrocarbons for fuels containing any desired ratio of open-chain andclosed-chain hydrocarbons, the process comprising: passing a feedstockcomprising ethylene to a gas purification zone to remove water,providing a purified feedstock; passing the purified feedstock to afirst oligomerization stage to oligomerize the ethylene in the purifiedfeedstock by contacting the ethylene with a catalyst comprising a metaldeposited on a support at a temperature from about 40° C. to 220° C. toform a first oligomerization product, wherein the first oligomerizationproduct comprises a majority concentration of mixed olefins with acarbon number from about C4 to about C8; and passing the firstoligomerization product to a second oligomerization stage to oligomerizethe mixed olefins by contacting the mixed olefins with a solid acidcatalyst at a temperature from greater than 150° C. to about 450° C. toform a second oligomerization product, wherein the secondoligomerization product contains mixed linear olefins and branchedolefins with a carbon number from about C8 to about C23 in a yield ofgreater than or equal to 20%; converting ethanol in anethanol-containing feedstock over an acid catalyst to form a firstconversion product containing hydrocarbons with a carbon number fromabout C2 to about C12 and comprising a majority concentration ofclosed-chain mixed aromatic hydrocarbons and cycloparaffin hydrocarbons;alkylating the first conversion product to produce a second conversionproduct comprising a selected quantity of alkylated aromatichydrocarbons therein; and combining selected portions of the firstconversion product, the second conversion product, and/or the secondoligomerization product together to form a blend containing open-chainand closed-chain hydrocarbons that when hydrotreated yields a majorityof fuel range hydrocarbons boiling in the range of temperatures fromabout 120° C. to about 390° C.
 46. The process of claim 1, wherein thefirst hydrocarbon product is produced by contacting a feedstockcomprising ethanol with an acid catalyst thereby converting the ethanolto a first hydrocarbon product comprising hydrocarbons with a carbonnumber between about C2 and about C12 and comprising a majorityconcentration of aromatic hydrocarbons and cycloparaffin hydrocarbons.47. The process of claim 46, wherein the feedstock is contacted with theacid catalyst at a temperature of about 280° C. to about 500° C.
 48. Theprocess of claim 1, wherein the second hydrocarbon product is producedby alkylating the first hydrocarbon product.